Skip to main content

Full text of "The manufacture of pulp and paper : a textbook of modern pulp and paper mill practice"

See other formats 


ROBERTSON  PULP  &  PAPER  LAB, 
N.  C.  STATE  UNIVERSITY 
RALEIGH,  N.  C.  27607 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 

NCSU  Libraries 


http://www.archive.org/details/manufactureofpul04join 


THE  MANUFACTURE 

OF 

PULP  AND  PAPER 


VOLUME  IV 


Pulp  and  Paper  Manufacture 

IN  FIVE  VOLUMES 

An  OflBcial  Work  Prepared 
under  the   direction  of  the 

Joint  Executive  Committee  of  the 

Vocational  Education  Committees  of  the 

Pulp  and  Paper  Industry  of  the 

United  States  and  Canada 


Vol.     I — Mathematics,     How     to    Read 
Drawings,  Physics. 
II — Mechanics     and     Hydraulics, 

Electricity,  Chemistry. 
Ill — Preparation  of  Pulp. 
IV,  V — Manufacture  of  Paper. 


THE 

MANUFACTURE 

OF 

PULP  AND  PAPER 

A  TEXTBOOK  OF  MODERN  PULP 
AND     PAPER     MILL     PRACTICE 

Prepared    Under    the    Direction    of    the    Joint   Executive 

Committee  on  Vocational  Education  Representing 

the   Pulp    and    Paper    Industry    of    the 

United  States   and   Canada 


VOLUME  IV 


Preparation  of  Rags  and  Other  Fibers;  Treatment  of  Waste  Papers; 

Beating  and  Refining;  Loading  and  Engine  Sizing;  Coloring; 

Paper-Making  Machines 

Anthors:  E.  C   Tucker,  A.B.;  Ed.  T.  A.  Coughlin,  B.S.,  Ch.E.;  Arthur  B 

Green,    A.B.,    S.B.;    Ross    Campbell,    B.S.;    J.    W.    Brassington; 

Judson  A.  DeCew,  B.A.Se.;  C.  J.  West,  Ph.D.;  James 

Bevcridge;  and  others. 


First  Edition 


McGRAW-HILL  BOOK  COMPANY,  Inc. 
NEW  YORK:  370  SEVENTH  AVENUE 

LONDON:   6  &  8  BOUVERIE  ST.,  E.  C.  4 
1924 


Copyright,  1924,  by  the 

Joint  Executive  Committee  of  the  Vocatio>jal  Education  Committees 

OF  the  Pulp  and  Paper  Industry. 


All  Rights  Reserved, 
Including  Those  of  Translation. 


PRINTED   IN   THE   UNITED    STATES   OF   AMERICA 


THE    MAPLE    PRESS    COMPANY,    YORK.    PA. 


PREFACE 


In  numerous  communities  where  night  schools  and  extension 
classes  have  been  started  or  planned,  or  where  men  wished' to 
study  privately,  there  has  been  difficulty  in  finding  suitable 
textbooks.  No  books  were  available  in  English,  which  brought 
together  the  fundamental  subjects  of  mathematics  and  element- 
ary science  and  the  principles  and  practice  of  pulp  and  paper 
manufacture.  Books  that  treated  of  the  processes  employed 
in  this  industry  were  too  technical,  too  general,  out  of  date,  or  so 
descriptive  of  European  machinery  and  practice  as  to  be  unsuit- 
able for  use  on  this  Continent.  Furthermore,  a  textbook  was 
required  that  would  supply  the  need  of  the  man  who  must  study 
at  home  because  he  could  not  or  would  not  attend  classes. 

Successful  men  are  constantly  studying;  and  it  is  only  by 
studying  that  they  continue  to  be  successful.  There  are  many 
men,  from  acid  maker  and  reel-boy  to  superintendent  and  mana- 
ger, who  want  to  learn  more  about  the  industry  that  gives  them  a 
livelihood,  and  by  study  to  fit  themselves  for  promotion  and  in- 
creased earning  power.  Pulp  and  paper  makers  want  to  under- 
stand the  work  they  are  doing — the  how  and  why  of  all  the 
various  processes.  Most  operations  in  this  industry  are,  to  some 
degree,  technical,  being  essentially  either  mechanical  or  chemical. 
It  is  necessary,  therefore,  that  the  person  who  aspires  to  under- 
stand these  processes  should  obtain  a  knowledge  of  the  under- 
lying laws  of  Nature  through  the  study  of  the  elementary  sciences 
and  mathematics,  and  be  trained  to  reason  clearly  and  logically. 

After  considerable  study  of  the  situation  by  the  Committee 
on  Education  for  the  Technical  Section  of  the  Canadian  Pulp 
and  Paper  Association  and  the  Committee  on  Vocational  Educa- 
tion for  the  Technical  Association  of  the  (U.  S.)  Pulp  and  Paper 
Industry,  a  joint  meeting  of  these  committees  was  held  in  Buffalo 

V 


VI  PREFACE 

in  September,  1918,  and  a  Joint  Executive  Committee  was  ap- 
pointed to  proceed  with  plans  for  the  preparation  of  the  text,  its 
pubUcation,  and  the  distribution  of  the  books.  The  scope  of  the 
work  was  defined  at  this  meeting,  when  it  was  decided  to  provide 
for  preliminary  instruction  in  fundamental  Mathematics  and 
Elementary  Science,  as  well  as  in  the  manufacturing  operations 
involved  in  modern  pulp  and  paper  mill  practice. 

The  Joint  Executive  Committee  then  chose  an  Editor, 
Associate  Editor,  and  Editorial  Advisor,  and  directed  the  Editor 
to  organize  a  staff  of  authors  consisting  of  the  best  available  men 
in  their  special  hnes,  each  to  contribute  a  section  dealing  with  his 
specialty.  A  general  outline,  with  an  estimated  budget,  was 
presented  at  the  annual  meetings  in  January  and  February,  1919, 
of  the  Canadian  Pulp  and  Paper  Association,  the  Technical 
Association  of  the  Pulp  and  Paper  Industry,  and  the  American 
Paper  and  Pulp  Association.  It  received  the  unanimous  approval 
and  hearty  support  of  all;  and  the  budget  asked  was  raised  by 
an  appropriation  of  the  Canadian  Pulp  and  Paper  Association 
and  contributions  from  paper  and  pulp  manufacturers  and  allied 
industries  in  the  United  States,  through  the  efforts  of  the 
Technical  Association  of  the  Pulp  and  Paper  Industry. 

To  prepare  and  publish  such  a  work  is  a  large  undertaking; 
its  successful  accomphshment  is  unique,  as  evidenced  by  these 
volumes,  in  that  it  represents  the  cooperative  effort  of  the  Pulp 
and  Paper  Industry  of  a  whole  Continent. 

The  work  is  conveniently  divided  into  sections,  and  bound  into 
volumes  for  reference  purposes;  it  is  also  available  in  pamphlet 
form  for  the  benefit  of  students  who  wish  to  master  one  part 
at  a  time,  and  for  convenience  in  the  class  room.  This  latter 
arrangement  makes  it  very  easy  to  select  special  courses  of 
study;  for  instance,  the  man  who  is  specially  interested,  say,  in 
the  manufacture  of  pulp  or  in  the  coloring  of  paper  or  in  any 
other  special  feature  of  the  industry,  can  select  and  study  the 
special  pamphlets  bearing  on  those  subjects  and  need  not  study 
others  not  relating  particularly  to  the  subject  in  which  he  is 
interested,  unless  he  so  desires.  The  scope  of  the  work  enables 
the  man  with  but  little  education  to  study  in  the  most  efficient 
manner  the  preliminary  subjects  that  are  necessary  to  a 
thorough  understanding  of  the  principles  involved  in  the  manu- 
facturing processes  and  operations;  these  subjects  also  afford  an 
excellent  review  and  reference  textbook  to  others.     The  work 


PREFACE  vii 

is  thus  especially  adapted  to  the  class  room,  to  home  study, 
and  for  use  as  a  reference  book. 

It  is  expected  that  universities  and  other  educational  agencies 
will  institute  correspondence  and  class-room  instruction  in 
Pulp  and  Paper  Technology  and  Practice  with  the  aid  of  these 
volumes.  The  aim  of  the  Committee  is  to  bring  an  adequate 
opportunity  for  education  in  his  vocation  within  the  reach  of 
every  one  in  the  industry.  To  have  a  vocational  education 
means  to  be  familiar  with  the  past  accomplishments  of  one's 
trade,  and  to  be  able  to  pass  on  a  record  of  present  experience 
for  the  benefit  of  those  who  will  follow. 

To  obtain  the  best  results,  the  text  must  be  diligently  studied ; 
a  few  hours  of  earnest  application  each  week  will  be  well  repaid 
through  increased  earning  power  and  added  interest  in  the  daily 
work  of  the  mill.  To  understand  a  process  fully,  as  in  making 
acid  or  sizing  paper,  is  like  having  a  light  turned  on  when  one 
has  been  working  in  the  dark.  As  a  help  to  the  student,  many 
practical  examples  for  practice  and  study  and  review  questions 
have  been  incorporated  in  the  text;  these  should  be  conscien- 
tiously answered. 

This  volume  deals  with  the  manufacture  of  paper  in  the  same 
authoritative  and  comprehensive  manner  as  the  subject  of  the 
manufacture  of  pulp  was  covered  in  the  preceding  volume.  In 
spite  of  the  antiquity  of  the  paper  industry,  recent  developements 
have  been  remarkable.  There  is  still  almost  unlimited  oppor- 
tunity for  exhaustive  improvement  in  equipment  and  operation, 
and  further  advances  will  result  from  the  study  of  what  has 
already  been  accomplished.  The  progress  that  has  been  made 
in  paper  manufacture  is  expressed  in  the  carefully  prepared  and 
exceptionally  well  illustrated  text  of  this  volume  and  the  volume 
that  follows.  The  importance  of  paper — its  place  as  an  absolute 
necessity  in  civihzed  life — is  now  fully  recognized;  and  every  one 
should  be  interested  in  and  be  able  to  understand  the  descriptions 
herein  given  of  the  processes  and  equipment  involved  in  its 
manufacture.  Never  have  such  care  and  expense  been  devoted 
to  the  preparation  of  an  industrial  textbook. 

A  feature  of  this  series  of  volumes  is  the  wealth  of  illustrations, 
which  are  accompanied  by  detailed  descriptions  of  typical 
apparatus.  In  order  to  bring  out  a  basic  principle,  it  has  been 
necessary,  in  some  cases,  slightly  to  alter  the  maker's  drawing, 


viii  PREFACE 

and  exact  scales  have  not  been  adhered  to.  Since  the  textbook 
is  in  no  sense  a  "machinery  catalog,"  maker's  names  have  been 
mentioned  only  when  they  form  a  necessary  descriptive  item. 
Much  of  the  apparatus  illustrated  and  many  of  the  processes 
described  are  covered  by  patents,  and  warning  is  hereby  given 
that  patent  infringements  are  costly  and  troublesome. 

A  valuable  feature  of  this  work,  which  distinguishes  it  from  all 
others  in  this  field,  is  that  each  Section  was  examined  and 
criticised  while  in  manuscript  by  several  competent  authorities; 
in  fact,  this  textbook  is  really  the  work  of  more  than  one  hundred 
men  who  are  prominent  in  the  pulp  and  paper  industry.  With- 
out their  generous  assistance,  often  at  personal  sacrifice,  the 
work  could  not  have  been  accomplished.  Even  as  it  stands, 
there  are,  no  doubt,  features  that  still  could  be  improved.  The 
Committee,  therefore,  welcomes  helpful  criticisms  and  sugges- 
tions that  will  assist  in  making  future  editions  of  still  greater 
service  to  all  who  are  interested  in  the  pulp  and  paper  industry. 

The  Editor  extends  his  sincere  thanks  to  the  Committee  and 
others,  who  have  been  a  constant  support  and  a  source  of  in- 
spiration and  encouragement;  he  desires  especially  to  mention 
Mr.  George  Carruthers,  Chairman,  and  Mr.  R.  S.  Kellogg, 
Secretary,  of  the  Joint  Executive  Committee;  Mr.  J.  J.  Clark, 
Associate  Editor  and  Mr.  T.  J.  Foster,  Editorial  Advisor. 

The  Committee  and  the  Editor  have  been  generously  assisted 
on  every  hand;  busy  men  have  written  and  reviewed  manuscript, 
and  equipment  firms  have  contributed  drawings  of  great  value 
and  have  freely  given  helpful  service  and  advice.  Among  these 
kind  and  generous  friends  of  the  enterprise  are:  Mr.  M.  J.  Argy, 
Mr.  O.  Bache-Wiig,  Mr.  James  Beveridge,  Mr.  J.  Brooks  Bever- 
idge,  Mr.  H.  P.  Carruth,  Mr.  Martin  L.  Griffin,  Mr.  H.  R. 
Harrigan,  Mr.  Kenneth  T.  King,  Mr.  Maurice  Neilson,  Mr.  Elis 
Olsson,  Mr.  J.  S.  Riddile,  Mr.  George  K.  Spence,  Mr.  Edwin 
Sutermeister,  Mr.  F.  G.  Wheeler,  and  Bird  Machine  Co.,  Cana- 
dian IngersoU-Rand  Co.,  Claflin  Engineering  Co.,  Dominion 
Engineering  Works,  E.  I.  Dupont  de  Nemours  Co.,  General 
Electric  Co.,  Harland  Engineering  Co.,  F.  C.  Huyck  &  Sons, 
Hydraulic  Machinery  Co.,  Improved  Paper  Machinery  Co., 
E.  D.  Jones  &  Sons  Co.,  A.  D.  Little,  Inc.,  E.  Lungwitz, 
National  Aniline  and  Chemical  Works,  Paper  Makers  Chemical 
Co.,  Process  Engineers,  Pusey  &  Jones  Co.,  Rice,  Barton  &  Fales 
Machine  and  Iron  Works,  Ticonderoga  Paper  Co.,   Waterous 


PREFACE  ix 

Engine  Works  Co.,  Westinghouse  Electric  &  Manufacturing  Co., 
and  many  others,  particularly  the  authors  of  the  various 
sections,  who  have  devoted  so  much  time  and  energy  to  the 
preparation  of  manuscript,  often  at  personal  sacrifice. 

J.  Newell  Stephenson, 

Editor 

FOK   THE 

Joint  Executive  Committee  on  Vocational  Education, 
George  Carruthers,  Chairman,  R.    S.    Kellogg,    Secretary, 

T.  L.   Crossley,  R.   S.   Hatch,  G.  E.   Williamson. 

Representing  the  Technical  Sec-  Representing  the  Technical  As- 
tion  of  the  Canadian  Pulp  and  Paper  sociation  of  the  (U.  S.)  Pulp  and 
Association.  Paper  Industry. 

T.  L.  Crossley,  Chairman,  R.  S.  Hatch,  Chairman, 

George  Carruthers,  R.  S.  Kellogg, 

A.  P.  Costigane,  F.  C.  Clark, 

C.  Nelson  Gain,  W.  S.  Lucey, 

J.  N.  Stephenson.  Ernst  Mahler, 

J.  D.  Rue, 
A.  D.  Wood. 


CONTENTS 

Page 

Preface v 

SECTION  1 

Preparation  of  Rag  and  Other  Fibers 

Introduction 1-4 

Sources  of  Supply 4-6 

Classification  of  Rags 6-9 

Treatment  of  Rags  before  Cooking 9-17 

Cooking  of  Rags 17-30 

Bleaching,  Draining,  and  Losses 30-39 

Hemp,  Jute,  Seed-Hull  Fiber,  etc 39-46 

Esparto 46-54 

Straw  Pulp 54-59 

ExTamination  Questions 62 

SECTION  2 
Treatment  of  Waste  Papers 

Use  and  Value  of  Waste  Papers 1-3 

Methods  of  Recovery 3-8 

Mill  Sorting 9-16 

Dusting  the  Papers 17-19 

Paper  Shredders 19-25 

Purchasing  Paper  Stock 25-28 

Cooking  Processes 28-57 

Treatment  of  Cooked  Paper  Stock 57-70 

Examination  Questions 71-72 

SECTION  3 

Beating  and  Refining 

Introduction 1-4 

Types  of  Beaters 4-19 

Care  of  Beaters 19-21 

Beater-Room  Equipment 22-36 

Condition  and  Handling  of  Pulps  and  Half-Stuff 37-45 

Theory  of  Beating 45-64 

The  Jordan  Refining  Engine 65-68 

Special  Types  of  Refining  Engines 68-70 

Bibliography 71-77 

Examination  Questions 79-80 

xi 


xii  CONTENTS 

SECTION  4 

Loading  and  Engine  Sizing 

PART  1 

Page 

Fillers 1-3 

.soukcks  and  character  of  fillers 4-16 

Analysis  of  Fillers 17-22 

PART  2 

Engine  Sizing — Historical 23-24 

Materials  Used  in  Sizing 24-28 

The  Sizing  Process 28-44 

Sizing  Different  Kinds  of  Paper 45-47 

Examination  Questions 49 

SECTION  5 
Coloring 

Introduction 1-4 

Classification  of  Coloring  Materials 4-11 

Sources  and  Manufacture  of  Aniline  Dyes 11-13 

Standardization  of  Dyestuffs 13-15 

Testing  of  Dyestuffs 15-31 

Color-Storage  and  Preparation  Rooms 31-34 

Details  of  Coloring  Process 34-40 

Color  Formulas 40-46 

Calender  and  Other  Methods  of  Coloring 46-52 

Examination  Questions 53-54 

SECTION  6 

Paper-Making  Machines 

PART  1 

General  Description 1-3 

Paper-Machine  Room 3-5 

Important  Auxiliary  Equipment 5-26 

Screens 26-34 

Origin  of  Modern  Paper  Machine 34-38 

Fourdrinier  Part  of  the  Paper  Machine 38-41 

Details  of  Fourdrinier  Part 41-74 

Management  of  Fourdrinier  Part 74-80 

Operating  Details  and  Troubles 80-95 

Examination  Questions 97-98 


CONTENTS  xiii 

PART  2 

Page 

De-Watering  the  Paper 99-101 

Description  of  Press  Part 101-106 

Details  of  Press  Part 106-118 

Management  and  Care  of  Press  Part 118-137 

Examination  Questions 139-140 

PART  3 

The  Smoothing  Rolls 141-144 

A  Typical  Dryer  Part 144-150 

Details  of  Dryer  Part 150-159 

Operation  and  Management  of  Dryers 159-164 

Dryer  Felts  and  Evaporative  Effects 164-176 

Examination  Questions 177-178 

PART  4 

The  Calender  End 17&-187 

Reels 187-196 

Slitters  and  Winders 196-205 

Winding  Troubles 205-207 

Examination  Questions 209-210 


SECTION  1 

PREPARATION  OF  RAG 
AND  OTHER  FIBERS 


By  E.  C.  Tucker,  A.  B. 


RAGS  AND  RAG  FIBERS 


INTRODUCTION 

1.  A  Brief  History  of  the  Use  of  Rags  in  Paper  Making. — The 

earhest  human  records  were  made  on  stone;  in  some  countries 
scratched  or  chiseled,  in  others  written  with  chalk  or  colored  ore. 
Other  and  more  convenient  substances  used  later  in  various 
places  were,  pieces  of  wood — as  bamboo,  bark,  leaves — and 
prepared  skins,  as  parchment  and  vellum.  At  a  very  early  date, 
the  Egyptians  prepared  a  writing  material  from  papyrus,  a  tall 
reed  growing  in  the  Nile,  and  called  it  also  papyrus,  whence  our 
word  paper.  It  was  made  by  peehng  off  the  layers  of  the  stem, 
laying  the  long  ones  side  b}-  side  until  a  strip  of  the  desired  width 
was  obtained,  then  crossing  them  with  short  pieces.  The  sap 
served  as  an  adhesive;  and,  after  drying  in  the  sun,  the  papyrus 
could  be  rubbed  to  a  surface  that  could  be  written  on  with  ink. 
A  shortage  of  papyrus  in  Asia  ]\Iinor  resulted  in  the  invention 
of  parchment,  a  specially  dried  calf  or  goat  skin,  filled  by  rubbing 
in  chalk.  Because  of  a  similar  famine  in  Rome,  hoards,  covered 
with  wax,  were  used;  they  were  written  on  with  a  sharp  instru- 
ment called  a  stylus.  Several  layers  of  wax  were  sometimes  put 
on  the  same  tablet. 

2.  The  earl}'  Greeks  wrote  letters,  notes,  mortgages,  etc.  on 
broken  pieces  of  pottery.  The  Chaldeans  and  Syrians  wrote 
their  records  in  soft  clay  bricks,  which  were  then  baked. 
Librarians  must  have  used  wheelbarrows! 

§1  1 


2       PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

The  Chinese  were  the  first  real  pulp  and  paper  makers.  They 
soaked  pieces  of  bamboo  in  pits  of  lime  water  and  separated  the 
fibers  by  pounding.  Rag  and  other  fibers  were  also  used,  the 
process  of  making  the  paper  being  essentially  the  same  as  in  use 
now  in  making  hand-made  papers. 

3.  At  the  dawn  of  the  Christian  era,  paper  making  from  rag 
fibers  was  a  well-established  art  in  China.  From  there  the 
secrets  of  the  process  spread  westward,  and  were  carried  to 
Europe  by  the  invasions  of  the  barbaric  tribes.  During  the 
middle  ages,  the  process  was  improved  and  developed,  and  by 
the  end  of  the  fourteenth  century  it  was  firmly  established 
throughout  southern  Europe. 

In  England,  the  development  was  very  slow,  for  it  was  not 
until  three  centuries  later  that  the  industry  took  firm  hold  there. 
As  would  be  expected,  the  delay  with  which  the  industry  was 
developed  in  England  was  further  reflected  in  this  country,  and 
it  was  not  until  the  last  half  of  the  eighteenth  century  that  paper 
making  became  common  here,  although  the  first  mill  was 
established  in  1690,  and  the  industry  developed  without 
interruption. 

4.  Early  Methods  of  Converting  Rags  into  Paper. — The  early 

phases  of  the  development  of  paper  making  are  interesting. 
The  first  process  for  converting  the  rags  into  paper  was  crude 
and  primitive.  The  rags  were  washed,  and  were  then  steeped  in 
closed  vessels  for  several  days.  During  this  treatment,  a 
fermentation  process  took  place  which  brought  the  mass  to  a 
pasty  consistency.  This  pulp  was  then  diluted,  transferred 
to  the  vat,  and  made  into  sheets  on  a  hand  mold.  (See  Hand- 
made Papers,  Vol.  V.)  The  first  advance  from  this  method  came 
with  the  introduction  of  stamping  rods,  to  beat  the  rags  into 
pulp ;  and  this  was  the  process  in  use  in  practically  all  of  the  small 
mills  previous  to  1750.  The  rags  were  washed,  and  were  then 
transferred  to  oak  tubs  or  mortars,  partly  filled  with  water. 
Here  the  rags  were  beaten  and  pulped  by  stamping  rods, 
which  were  encased  with  an  iron  shoe  at  one  end.  In  most 
of  the  mills,  these  stamping  rods  were  operated  b}^  power 
from  a  small  stream — in  a  few  cases  they  were  operated  by 
hand.  By  this  method,  using  water  power,  from  100  to  125 
pounds  of  rags  would  be  reduced  to  pulp  in  24  hours  in  a 
typical  mill. 


§1  RAGS  AND  RAG  FIBERS  3 

5.  During  the  period  from  1750  to  1800,  the  Hollander  beater 
engine  was  developed  and  brought  into  general  use.  This  was 
a  small  and  early  type  of  the  boating  engine  so  well  known  today. 
Its  introduction  brought  the  first  decided  change  in  manufactur- 
ing equipment.  It  improved  quality,  increased  production,  and 
made  possible  the  later  rapid  growth  of  the  industry. 

6.  Paper-Making  Raw  Materials.^ — Prior  to  1860,  rag  fibers, 
cotton  and  linen  (with  small  quantities  of  jute  and  hemp), 
formed  the  total  source  of  paper-making  raw  materials.  Rags 
were  used  in  all  grades  of  paper,  from  news  and  wrapping  paper  to 
writing  paper.  This  condition  made  rags  very  scarce,  in  spite 
of  large  importations  from  Europe.  In  1850,  more  than  twenty 
million  pounds  of  rags  were  imported  by  the  United  States,  and 
still  the  mills  were  short  of  raw  material.  The  newspapers  and 
periodicals  of  those  days  were  full  of  pleas  from  paper-mill  pro- 
prietors, asking  the  people  to  save  their  rags  for  some  particular 
paper  mill.  The  difficulty  in  obtaining  a  sufficient  supply  of 
raw  material  was  the  determining  factor  in  the  industry. 
Expansion  was  almost  impossible. 

The  discovery  of  the  processes  of  making  pulp  from  wood — the 
soda,  sulphite,  and  groundwood  processes — finally  relieved  this 
situation,  and  gave  the  industry  the  opportunity  to  grow. 

7.  At  the  present  time,  most  of  the  rags  go  into  the  class  of 
paper  known  as  fine  writing,  and  for  this  type  of  paper  the  fiber 
from  cotton  or  linen  cloth  has  no  equal;  large  quantities  of  low- 
grade  rags  are  used  for  roofing  papers,  while  burlap,  strings 
(jute)  and  hemp  rope  are  used  for  strong  wrapping  papers 
(manilas).  These  fibers  are  prepared  for  use  directly  in  the 
paper  mill,  as  distinguished  from  wood  fibers,  which  receive 
their  first  treatment  in  the  pulp  mill.  For  this  reason,  and 
because  of  the  considerable  similarity  in  processes  and  apparatus, 
the  preparation  of  straw  and  esparto  grass  is  also  included  in 
this  Section.  The  treatment  of  waste  papers  is  covered  in 
another  Section. 

Note. — Cotton^  (gossypium).  The  cotton  fiber,  which  is  the  basis  of 
most  rag  papers,  consists  of  a  single  hair-like  cell,  which  is  flattened  and 
twisted  when  fully  ripe.  This  appearance  is  a  characteristic  of  fully  matured 
cotton;  it  is  not  shown  by  unripe  fiber  or  by  that  which  has  been  injured 

^  Data  on  the  characteristics  of  paper-making  fibers,  given  in  these 
notes,  are  based  on  information  derived  from  Chemistry  of  Pulp  and  Paper 
Making,  by  E.  Sutermeister.     See  also  Section  1,  Vol.  III. 


4       PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

during  growth.  The  fibers  form  the  covering  of  the  cotton  seed,  and  they 
are  removed  from  the  seed  by  ginning.  Tlie  length  of  the  cotton  fiber  varies 
from  2  to  5.6  cm.,  and  the  diameter  varies  from  0.0163  to  0.0215  mm.  The 
cell  walls  of  mature  cotton  are  thin,  and  they  often  present  a  granulated 
appearance  or  highly  characteristic  cross  markings.  IMuller  has  analyzed 
raw  cotton,  with  the  following  results : 

Per  Cent 

Water 7 .  00 

Cellulose 91 .35 

Fat 0.40 

Aqueous  extract  (containing  nitrogenous  substances) .  0.50 

Ash 0.12 

Cuticular  substance  (by  difference) 0.63 

Total 100.00 


SOURCES  OF  SUPPLY 

8.  New  Rags,  or  Table  Cuttings. — The  supply  of  new  rags  for 
paper  making  comes  largely  from  textile  or  garment  factories, 
where  cuttings  and  scrap  ends  of  cloth  are  collected  as  by- 
products. The  total  amount  of  cuttings  available  from  this 
source  of  supply  is  estimated  at  40,000  tons  per  year.  The 
only  other  use  for  this  material  seems  to  be  the  re-spinning  of 
white  knitted  goods,  and  this  in  quantity  only  when  the  price 
of  raw  cotton  is  high. 

This  waste  material  is  usually  sold  to  a  broker  or  middleman, 
who  takes  the  entire  accumulation  of  the  individual  factory; 
and  it  may  include  everything,  from  the  floor  sweepings  to 
the  choicest  clippings  of  white  linen  or  cotton.  The  middleman 
usually  repacks  this  material  and  then  sells  it  to  the  paper  mills 
that  use  the  different  grades. 

9.  Old  Rags. — The  source  of  supply  of  old  rags  is  quite  differ- 
ent. In  the  first  place,  it  is  much  more  flexible.  Being  a  waste 
product,  so  common  to  every  home,  there  is  little  likelihood  of  a 
shortage;  for  a  rise  in  price  will  always  bring  out  rags.  We  are 
all  familiar  with  the  grotesque  figure  that  travels  our  streets 
and  alleys  buying  "ra — gs"  from  the  housewife.  His  capital 
consists  of  a  dejected  horse  and  a  dilapidated  wagon.  Each 
night  he  sells  his  day's  collection  to  another  rag  man  who  owns  a 
small  warehouse,  and  who  buys  these  mixed  rags  and  l)ales 
them  in  carload  lots,  for  sale  to  the  grader.     The  grader  sorts 


§1  RAGS  AND  RAG  FIBERS  5 

the  rags  for  re-sale  (sometimes  directly  and  sometimes  through  a 
broker)  to  the  paper  mill,  in  the  case  of  cottons,  or  to  the  shodd}^ 
mill,  in  the  case  of  woolens.  The  following  figures  give  a  slight 
idea  of  what  a  thousand  pounds  of  mixed  rags  contain. 

Paper-Makixg  Rags 

Lb. 

No.  1  whites 25 

No.  2  whites 50 

Whites  and  blues 225 

Jute  bagging 125 

Roofing  stock 250 

675 
Non-Paper-Making  Rags 

Lb. 

Soft  woolens 20 

Hard  woolens 125 

Mixed  linseys  (half  wool  and  half  cotton) 20 

Wiping  rags 60 

Quilts  and  white  batting 85 

Rubbish 15 

325 

Total 1000  lb. 

10.  Uses  of  Rags. — Xo.  1  whites.  No.  2  whites,  and  whites 
and  blues,  (known  also  as  either  two's  and  blues  or  thirds  and 
blues)  are  used  for  writing  paper,  and  the  specifications  for  each 
of  these  grades  will  be  found  in  Arts.  13  and  14.  The  jute  bagging 
is  used  by  the  wrapping-paper  mill,  and  the  roofing  rags  are  used 
for  making  roofing  paper.  This  is  the  lowest  grade  of  stock; 
it  includes  everji;hing,  so  long  as  it  is  rag. 

The  woolen  rags  go  to  the  shodd}'  mills;  they  bringby  far  the 
highest  prices  of  any  of  the  grades. 

Wiping  rags  are  used  by  machine  shops,  etc.,  and  consist  of 
large  pieces  of  good,  sound  colored  cloth. 

Quilts  and  batting  go  to  the  mattress  industrj\  The  rubbish 
consists  of  such  material  as  old  straw  hats,  shoes,  etc.,  which 
must  be  baled  and  carted  to  the  dump. 

11.  Transporting  and  Handling  Rags. — Rags  are  transported 
and  handled  in  machine-pressed  bales  that  weigh  from  400  to 
1000  pounds,  depending  on  the  size  and  type  of  press.     The 


6       PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

hand  baling  press  is  still  largely  used;  it  is  by  far  the  most 
economical  method  of  baling  where  only  a  small  number  of  bales 
are  made  each  day.  With  this  type  of  press,  two  men  will  turn 
out  from  10  to  15  bales  a  day. 

Where  the  volume  of  baling  to  be  done  is  large  enough,  the 
power  press  is  of  course  more  economical.  There  are  several 
types  of  those  presses  on  the  market  any  one  of  which  does 
excellent  work.  A  bale  weighing  600  to  800  pounds  is  large 
enough  for  convenient  handling  in  the  mill. 


CLASSIFICATION  OF  RAGS 


SPECIFICATIONS 

12.  General  Specifications. — There  are  certain  general  rules 
which  should  apply  to  all  grades.  Rubber,  for  example,  in  any 
form  is  a  distinct  menace  to  the  manufacture  of  good  paper; 
and  it  should  be  generally  understood  that  rubber  is  not  to  be 
included  in  any  of  the  packings  of  rags  that  are  to  be  used  for 
the  manufacture  of  writing  paper. 

All  grades,  new^  and  old,  must  be  free  of  rubber,  leather,  wool, 
silk,  paper  or  muss,  unless  otherwise  specified.  It  is  recom- 
mended that  where  a  description  of  any  grade  is  not  available, 
the  material  is  to  be  sold  on  specified  sample. 

Other  general  specifications,  which  should  cover  all  grades  of 
rags,  unless  they  are  sold  strictly  on  representative  samples,  are : 
the}^  should  be  dry,  and  they  should  be  free  from  paint,  grease, 
and  other  foreign  materials. 


SPECIFICATIONS  BY  GRADES 

13.  Old  Rags. — Old  rags  are  divided  into  various  grades,  each 
of  which  has  its  own  trade  name  and  specifications,  which  are  as 
follows  for  old  rags: 

Extra  No.  1  white  cottons  consist  of  large,  clean,  white  cottons, 
free  from  knits,  ganzies,  canvas,  lace  curtains,  collars,  cuffs,  shirt 
bosoms,  bed  spreads,  new  cuttings  and  stringy  or  mussy  rags. 

No.  1  white  cottons  consist  of  clean  white  cottons,  free  from 
lace  curtains,  ganzies  and  canvas.     Need   not   be  so  large  as 


§1  RAGS  AND  RAG  FIBERS  7 

Extra  No.  1  white  cottons.  Must  not  contain  stringy  or 
mussy  rags. 

No.  2  whites  consist  of  soiled  white  cottons,  free  from  dump 
rags,  street  rags,  scorched  rags,  paint,  greasy  rags,  or  oily  rags. 
Also  free  from  button  strips  and  seams  from  higher  grades  of 
whites. 

Mixed  whites  should  contain  at  least  40%  of  No.  1  whites 
and  not  more  than  60%  of  No.  2  whites.  They  must  not  contain 
any  of  the  material  prohibited  in  the  grades  of  which  they  are 
composed. 

Street  whites  should  consist  of  soiled  white  cottons  from 
street  or  dump  collection.  They  are  likely  to  contain  some 
foreign  material,  resulting  from  the  manner  in  which  they  are 
collected,  but  the  rags  must  be  dry. 

Twos  and  blues  should  be  rags  of  strictly  house  collection, 
and  should  consist  of  No.  2  white  cottons  and  light  blue 
checks  and  prints.  They  should  not  contain  the  seams  or 
buttons  taken  from  higher  grades  of  whites,  nor  should 
they  contain  dark  blues  of  any  description.  They  should  not 
contain  old  corsets,  small  pieces  of  new  rags,  or  rags  smeared 
with  paint,  oil,  or  grease,  nor  should  they  contain  any  scorched 
rags. 

Thirds  and  blues  should  be  rags  of  strictly  house  collection, 
and  may  contain  light  pinks,  greens,  and  blues,  but  should  be  free 
from  dark  reds,  yellows  and  blacks,  from  quilts  and  feather 
ticks,  canvas,  tents  and  awnings,  seams  and  stoppings  from 
higher  grade  rags,  from  rags  smeared  with  paint,  oil,  or  grease, 
and  from  small  pieces  of  new  rags  or  fine  cut  mussy  rags. 

Miscellaneous  blues  should  be  rags  of  all  colors,  free  from 
solid  black  or  satinet.  Street  or  dump  rags  must  not  be  present 
in  excess  of  25%. 

Old  blue  overalls  are  to  contain  clean,  blue  overalls  only^  free 
from  oil,  grease  or  paint,  and  are  understood  to  be  free  from 
miners'  garments. 

Black  cotton  stockings  are  to  consist  entirely  of  black  cotton 
stockings,  but  white  feet  or  edgings  are  permitted. 

White  cotton  batting  should  contain  only  clean  white  cotton 
from  quilts,  mattresses  and  comforters;  must  be  stripped  of  all 
rags. 

White  cotton-filled  quilts  should  be  quilts  filled  with  white 
cotton  batting  onl}-. 


8       PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

No.  1  white  old  lace  curtains  are  to  contain  only  clean,  white 
lace  curtains,  free  from  starchy,  knitted  or  crocheted  material. 

Besides  these  grades  there  are  special  classifications,  such  as 
underwear,  flannelettes,  hosiery,  tarpaulins,  filter  press  canvas, 
strings,  rope,  burlap,  roofing  stock,  etc. 

14.  New  Rags. — For  new  rags,  the  names  of  the  grades  and 
their  specifications  are: 

No.  1  white  shirt  cuttings,  heavy,  are  to  consist  of  white 
cuttings  such  as  accumulate  from  shirt  factories  and  similar 
sources;  must  be  strictly  table  cuttings  and  are  to  be  free  of 
starchy  or  loaded  material.  B.V.D.  cuttings  (dimity)  may  be 
included. 

No.  1  white  shirt  cuttings,  lawns,  may  contain  materials  of 
lighter  weight  than  heavy  shirt  cuttings;  they  must  be  table 
cuttings  and  free  of  starchy  or  loaded  material. 

No.  2  white  shirt  cuttings  are  to  consist  of  white  shirt  cuttings 
and  lawns,  consisting  of  house  to  house  and  shop  collections, 
and  not  of  table  cuttings;  may  contain  a  small  percentage  of 
black  threads,  muss  and  soiled  material;  are  to  be  free  from  oily 
rags. 

No.  1  bleached  strips,  white  or  gray,  are  to  consist  of  strips  of 
white  or  gray  cotton  cuttings,  coming  from  bleacheries;  must  be 
clean. 

No.  1  soft  unbleached  cotton  are  to  consist  only  of  unbleached 
cuttings  of  a  character  similar  to  white  shirt  cuttings,  heavy. 
Must  be  free  of  starchy  or  loaded  rags,  Canton  flannels,  shivy 
rags  and  drills. 

No.  1  bleached  shoe  cuttings  should  be  table  cuttings  of  a 
nature  used  in  lining  shoes;  are  to  be  free  of  pasted  stock. 

No.  2  bleached  shoe  cuttings  are  the  same  as  No.  1,  but  may 
contain  pasted  stock. 

No.  1  unbleached  shoe  cuttings  are  to  be  the  same  as  No.  1 

bleached  shoe  cuttings,   with  the  exception  that  they  are  to 

consist  of  unbleached  cuttings  and  are  to  be  free  of  pasted  stock. 

No.  2  unbleached  shoe  cuttings  are  the  same  as  No.  1,  but  may 

contain  pasted  stock. 

No.  1  fancy  shirt  cuttings  are  to  be  such  table  cuttings  as 
accumulate  from  shirt  factories  and  similar  sources,  consisting 
of  white  background  with  colored  stripes. 

No.  2  fancy  shirt  cuttings  are  to  be  composed  of  the  same 
material  as  No.  1  fancy  shirt  cuttings,  with  the  exception  that 


§1  RAGS  AND  RAG  FIBERS  9 

they  need  not  be  table  cuttings;  but  must  consist  of  material 
coming  from  house  to  house  and  shop  collections;  may  contain 
black  threads  and  soiled  pieces. 

Blue  overall  cuttings  are  to  be  such  table  cuttings  as  accumu- 
late from  overall  factories  and  similar  sources.  This  grade 
should  be  accompanied  by  sample  showing  whether  the  weave 
consists  of  a  black-thread  or  white-thread  back. 

Washables  or  wrapper  cuttings  must  be  table  cuttings;  may 
contain  material  of  hghter  weight  than  fancy  shirts,  such  as 
cahcoes,  ginghams,  etc.;  may  contain  sohd  colors,  but  are  to  be 
free  of  reds  and  blacks; 

New  light  seconds  are  to  consist  of  sheer,  flimsy  rags,  light 
colored;  sohd  colors  are  to  be  admitted  or  white  backs  with 
colored  stripes.     Need  not  be  free  from  black  threads. 

Soiled  bleachery  rags  are  to  consist  of  cuttings  and  remnants 
coming  from  bleacheries;  may  be  soiled,  but  must  be  free  from 
oil  and  grease. 

No.  1  dark  prints  are  to  consist  of  all  dark  colors  and  unbleach- 
able  new  material. 

Cottonades  are  to  consist  of  coarse,  striped  cotton-garment 
cuttings  that  look  like  wool  but  are  free  from  wool.  Brown 
cuttings  and  striped  overalls  may  be  included. 

Besides  the  classes  given,  there  are  other  grades  and  subdivi- 
sions. An  interesting  article  on  Rags,  by  Howard  Atterbury, 
appeared  in  the  Pulp  and  Paper  Magazine,  1919,  p.  1103. 


TREATMENT  OF  RAGS  BEFORE  COOKING 


PRELIMINARY  THRASHING 

15.  The  Rag  Thrasher. — The  first  step  in  the  actual  prepara- 
tion of  rags  for  paper  making  is  the  preliminary  thrashing.    • 

The  bales  are  opened  up  and  the  rags  put  through  a  rag 
thrasher,  though  some  mills  pass  new  rags  directly  to  the  sorters. 
The  purpose  of  this  machine  is  to  open  the  rags  up  thoroughly, 
and  to  remove  the  loose  dirt  and  dust  that  may  be  present. 

The  rag  thrasher  consists  of  a  revolving  cylindrical  drum  A, 
Fig.  1,  about  40  inches  in  diameter,  from  which  protrude  hooks 
or  pins  B  for  thrashing  the  rags.  The  cylinder  is  enclosed,  and 
there  is  a  hopper  C  and  gate  D  on  one  side  for  feeding  in  the  rags, 


10     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

and  a  gate  E  on  the  other  side,  for  discharge  after  the  rags  are 
thrashed.  Under  the  cyUnder  is  a  coarse  screen  F,  which  allows 
the  dirt  to  drop  through,  but  which  holds  the  rags  in  contact  with 
the  drum.     At  the  top,  a  stick  of  timber  G,  about  12  inches 

from  the  drum,  serves  as  a  whip 
as  the  rags  beat  against  it.  Fine 
dust  held  in  suspension  is  re- 
moved by  a  suction  fan  through 
the  pipe  H.  The  dirt  is  shoveled 
out  from  below  the  screen. 

In  operation  the  hopper  is 
filled,  then  the  gate  is  opened, 
and  the  rags  are  allowed  to  slide 
into  the  thrasher.  After  4  or  5 
minutes'  thrashing  the  rags 
are  discharged  by  raising  the 
gate  on  the  other  side.  They 
are  then  ready  for  the  sorters. 

16.  Thrasher  Dust  and  Loss 
in  Weight. — ^Loss  in  weight  due 
to  the  amount  of  dust  and  dirt  taken  out  by  the  thrashers  depends 
largely,  of  course,  on  the  character  of  the  rags  going  in.  In  the 
case  of  new  table  cuttings,  the  loss  is  ver}^  small;  while  in  the  case 
of  street  whites,  it  may  run  as  high  as  8%  to  10  %  or  higher. 


Fig.  1. 


SORTING  AND  INSPECTING 

17.  Sorting  Rags. — From  the  thrasher,  the  rags  usually  are 
loaded  into  baskets  and  turned  over  to  women,  who  strip  and 
sort  them.  These  sorters  work  at  tables,  Fig.  2,  which  are  really 
shallow  boxes  with  a  coarse  screen  bottom.  Large  scythe-like 
kijives  are  used  for  stripping  buttons,  ripping  seams,  cutting 
large  rags,  etc.  In  the  case  of  new  rags,  there  is  usually  very 
little  stripping  to  do.  The  sorters  in  this  case  look  particularly 
for  foreign  material,  such  as  metal,  rubber,  leather,  etc.,  that 
must  be  taken  out,  and  also  for  the  occasional  pieces  of  silk  or 
wool  or  paper  that  may  be  there.  Pockets  are  always  searched; 
the  findings  include  knives,  rings,  money  and  trash. 

In  the  case  of  old  rags,  the  sorter's  work  is  more  difficult. 
These   old    rags   consist   mainly   of   cast-off   cotton    garments. 


§1 


RAGS  AND  RAG  FIBERS 


11 


12     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

These  garments  must  first  be  stripped  on  the  knife;  that  is,  the 
buttons  arc  stripped  off,  the  pockets  and  heavy  seams  ripped  up, 
and  all  metal  is  taken  off.  When  this  is  finished,  the  rags  are 
graded  as  to  color,  where  this  is  necessary',  separate  baskets 
receiving  the  different  grades  and  colors;  for  instance,  yellows 
and  reds,  known  as  "hard"  colors,  as  they  are  hard  to  bleach, 
are  saved  for  dark-colored  paper.  The  strippings  and  discarded 
stock  make  what  the  paper  maker  knows  as  muss,  and  this 
material  goes  into  the  manufacture  of  roofing  paper.  Good 
woolens  go  to  the  shoddy  industry. 

18.  Why  Rubber  and  Metal  Are  Avoided. — Perhaps  the  reader 
is  wondering  why  the  paper  maker  speaks  so  often  of  rubber  and 
metal,  and  is  so  anxious  to  avoid  them.  It  is  due  to  the  desire 
on  his  part  to  make  clean  paper.  Hold  a  sheet  of  writing  paper 
up  to  the  light  and  look  for  the  dirt.  Now  rubber  and  metal 
are  not  affected  by  the  cooking,  the  washing,  or  the  bleaching. 
Once  in,  they  go  straight  through  the  process,  only  getting  cut  up 
into  small  pieces  and  finally  spreading  through  the  whole  web 
of  paper.  "But,"  one  may  ask,  "How  is  it  that  you  sometimes 
find  such  things  as  rubber  in  new  cuttings  of  cotton  cloth?" 
It  is  there  because  of  the  large  amount  of  rubber  used  in  making 
cotton  garments.  There  are  rubber  waist  bands,  sleeve  bands, 
dress  shields  or  goods  waterproofed  or  pasted  together  with 
rubber.  Such  things  as  these,  carelessly  allowed  to  go  in  with 
good  material,  cause  losses  of  thousands  of  dollars  annually  to 
the  paper  industry.  Constant  alertness  is  the  only  safeguard 
against  troubles  of  this  sort. 

19.  Inspection  of  Rags. — Rags  coming  from  the  sorters  are 
usually  sent  to  the  inspectors  or  "over-lookers."  These  women 
go  over  the  rags  again  very  carefully,  to  make  certain  that  all  of 
the  objectionable  material  is  removed  from  the  rags  before  it  is 
passed  on  to  the  next  process.  The  rag  sorters  must  do  con- 
scientious work,  if  the  mill  is  to  make  clean  paper.  Workers 
in  the  rag  room  are  usually  paid  a  certain  amount  per  pound  for 
rags  sorted.  This  weighing  is  also  a  check  on  the  quality  of  rags 
and  quantity  used. 

20.  Equipment  of  Rag-Sorting  Room. — The  equipment  of 
the  rag-sorting  room  is  not  elaborate.  The  rags  are  handled  in 
large  baskets,  which  are  provided  with  casters,  for  ease  of  moving 
from  place  to  place.     The  sorters  work  on  tables  provided  with 


§1  RAGS  AND  RAG  FIBERS  13 

half-inch-mesh  wire  screens  on  the  working  surface,  this  allows 
dirt,  loose  buttons,  etc.,  to  drop  through  into  a  box.  Each  of 
the  sorters  has,  in  addition,  the  stripping  knife,  set  up  in  a 
convenient  place  on  the  table  or  screen  at  which  she  works;  this 
is  a  source  of  accidents,  usually  of  a  minor  nature,  but  likely 
to  cause  infection;  even  a  scratch  should  be  given  first-aid 
treatment. 

Particular  attention  must  always  be  given  to  the  ventilation 
of  the  rag  room,  and  a  special  ventilating  system  should  be 
provided  to  remove  the  dust  and  lint  that  always  comes  from 
handling  the  rags.  A  fan  usually  draws  the  dusty  air  in  a 
gentle  stream  from  just  below  the  screen  and  dehvers  it  to  a 
large  chamber,  where  the  air  practically  comes  to  rest,  and  the 
dirt  settles  out. 


CUTTING  AND  DUSTING 

21.  Reason  for  Cutting. — As  the  rags  come  from  the  sorters 
and  inspectors,  they  are  in  fairly  large  pieces.  In  order  to 
prevent  them  from  roping,  to  produce  uniform  half-stuff  (washed 
rags),  and  to  facilitate  handling  all  along  the  line,  the  rags  are 
cut  into  pieces  averaging  in  area  from  10  to  20  square  inches. 
For  many  years  this  work  was  done  by  women;  now,  however, 
the  rag-cutting  machine  is  practicall}^  always  used,  except  in  the 
case  of  linen  rags,  where  the  hand-cutting  of  rags  is  still  quite 
general. 

22.  Rag  Cutters. — The  essentials  of  this  cutter,  Fig.  3,  are  a 
revolving  knife  cutting  against  a  bed  knife  (like  a  lawn  mower), 
and  the  means  of  feeding  the  rags  to  this  knife.  In  many  of  the 
mills,  two  cutters  in  tandem  are  used.  Tandem  cutters  are 
set  at  right  angles  so  as  to  cut  the  rags  in  both  directions. 

23.  One  of  the  most  recent  machines  on  the  market  is  the 
rag  cutter,  shown  in  Fig.  3.  This  machine  uses  slitters  before 
the  knife,  and  its  operation  is  as  follows:  The  rags  are  placed 
in  the  feed  apron  U  at  the  top,  and  from  there  thej^  fall  in  between 
the  corrugated  knives,  or  slitters  X,  which  constantly  rotate  and 
slit  the  rags  into  strips  lengthwise.  The  rags  are  stripped  off 
these  slitters  by  another  set  of  corrugated  rolls,  and  clearers, 
and  fall  into  the  intermediate,  or  slat,  apron.  This  carries  the 
strips  along  and  feeds  them  endwise  to  the  fly  knife  A,  which 


14     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

turns  against  a  stationary  bed  knife  and  chops  off  the  strips  into 
rectangular  blocks.  The  cut  rags  then  fall  to  the  delivery  apron 
W,  which  carries  them  to  the  duster.  All  gears  should  be 
enclosed  and  care  taken  to  keep  hands  from  the  knives.  The 
bed  knife  is  lowered  or  lifted  by  means  of  hand  wheels  H  and 
screws,  so  as  to  regulate  the  distance  from  edge  of  bed  knife  to 
flv  knife  .4. 


Fig.  3. 


24.  Dusters. — Rags,  coming  from  the  rag  cutter,  carry  with 
them  the  dust  produced  by  the  cutting  operation.  This  dust  is 
too  short-fibered  to  be  of  use,  and  would  be  lost  in  the  later 
processes;  it  also  carries  with  it  a  verj^  considerable  amount  of 
dirt,  which  has  to  be  taken  out,  if  clean  paper  is  to  be  made. 
For  this  purpose,  different  types  of  dusters  are  in  use.  Very 
often  the  rags  are  discharged  from  the  rag  cutter  to  a  railroad 
duster.  In  this  type  of  duster,  revolving  drums  A,  Fig.  4,  with 
pins  or  teeth  arranged  helically  around  the  drum,  carry  the  rags 
over  fine  screens  C.  This  type  of  duster  is  very  simple.  The 
rags  are  fed  in  at  D ;  after  passing  the  screen,  they  are  deflected  to 


§1 


RAGS  AND  RAG  FIBERS 


15 


the  next  drum  bj'  the  shape  of  the  hood  at  E.  This  duster  is 
rather  harsh  in  its  treatment  of  the  rags,  and  the  fiber  loss  is 
considerable.  On  the  other  hand,  the  harsh  treatment  elimi- 
nates a  large  amount  of  dirt,  so  that  its  use  is  common  on  old 
rags.  The  dirt  collects  in  the  box  below  the  screen.  The  rags 
usually  fall  from  the  outlet  F  upon  an  apron  conveyor. 


Fig.  4. 


Another  type  often  used  is  the  fan,  or  wing,  duster.  Fig.  5. 
Here  the  rags  are  blown  through  the  duster  b}-  a  revolving  drum 
A,  with  wings  B  arranged  helically.  At  the  same  time,  the  out- 
side screen  C  revolves  in  the  opposite  direction.  D  is  the  dust 
outlet.  This  makes  an  excellent  duster,  and  is  a  type  very 
generally  used.  Here  the  treatment  is  not  so  severe,  and  the 
fiber  loss  is  less. 


IG 


PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 


The  cut  rags  are  handled  from  the  rag  cutter  to  the  boiler  on 
aprons  or  in  chutes;  hence,  the  cutting,  dusting  and  loading  of 
the  boiler  really  take  place  as  one  operation.  Often,  however, 
it  is  necessary  to  prepare  and  pile  the  rags  in  advance. 


Fig.  5. 


25.  The  Magnetic  Roll. — In  spite  of  all  the  care  used  in  sorting 
and  inspecting  the  rags,  if  metal  is  present,  a  certain  amount  of 
it  always  gets  by.  The  magnetic  separating  roll,  Fig.  6,  has 
been  applied,  within  the  last  few  years,  for  removing  as  much  as 


Fig.  6. 


is  possible  of  this  material.  The  magnetic  pulley  A  is  placed  as 
the  driving  roll  on  one  of  the  aprons  B  carrying  the  cut  rags. 
Rags  C  containing  iron  or  steel  chng  to  the  pulley,  and  are  thus 
separated  from  the  other  rags  D. 


§1  RAGS  AND  RAG  FIBERS  17 

The  following  extract  from  a  letter  written  by  a  manufacturer, 
in  whose  mill  a  magnetic  separating  pulley  has  been  installed, 
gives  some  idea  of  what  this  pulley  can  accomplish : 

"Tests  show  that  we  are  taking  out  approximately  500  pieces  of  metal 
from  each  10,000  lb.,  of  old  rags,  run  through.  This  material  consists  of 
hooks  and  eyes,  metal  clasps,  tacks  and  nails,  metal  buttons,  pins,  needles, 
pieces  of  wire,  etc.,  which  are  not  detected  bj-  the  women  inspecting  the  rags. 
We  estimate  from  several  tests  that  this  is  about  75  %  of  the  material  which 
it  would  be  possible  to  take  out  in  this  way. 

Our  separator  roll  is  12  inches  in  diameter,  and  is  run  at  76.8  r.p.m. 
This  gives  us  an  apron  speed  of  241  feet  per  minute." 


QUESTIONS 

(1)  Name  some  of  the  materials  first  used  for  keeping  records. 

(2)  As  regards  source  of  supply  and  character,  how  do  new  rags  differ 
from  old  rags? 

(3)  (a)  Of  what  do  the  sortings  from  paper-making  rags  consist?     (6) 
what  uses  are  made  of  them? 

(4)  How  much  loss  is  suffered  in  thrashing? 

(5)  (a)  Mention  some  sources  of  rubber  and  iron  in  rags;  (h)  what  effect 
have  they  on  paper? 

(6)  Explain  one  type  of  duster  and  what  it  does. 


COOKING  OF  RAGS 


COOKING  AND  COOKING  LIQUOR 

26.  Purpose  of  Cooking. — It  may  now  be  asked  why  the  paper 
maker  cooks  the  rags  before  making  them  into  paper?  In  other 
words,  what  does  this  cooking  process  accomplish?  We  know 
that  wood  is  cooked  to  get  rid  of  the  impurities  (particularly 
lignin),  and  a  pure  cellulose  is  left.  Now  linen  and  cotton  fibers 
are  the  nearest  thing  to  be  had  in  nature  that  corresponds  to 
pure  cellulose;  but  the  rags  used  in  paper  making  contain  many 
undesirable  impurities,  which  should  be  removed.  First  of  all, 
the  cooking  softens  and  mellows  the  rag  by  removing  the  natural 
waxes  and  resinous  material  in  the  fiber.  In  addition,  it  removes 
the  dirt  and  grease  and  loosens  up  the  starch  and  loading  material. 
It  also  starts  the  color  in  rags  that  have  been  dyed,  and  thus 
renders  them  readily  bleachable.  In  some  mills,  it  is  the  practice 
to  take   certain  new  white   cuttings  directly  to   the   washing 


IS     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

engine,  leaving  out  the  cooking  process.  The  writer  does  not 
consider  this  to  be  the  best  practice,  although  it  is  feasible  in  the 
case  of  new  white  cuttings.  These  rags  are  harsh,  and  they  do 
not  respond  nearly  as  well  to  treatment  as  in  the  case  where  the 
same  rags  are  mellowed  by  the  cooking  process.  Uncooked  rags 
are  usually  rather  difficult  to  size  properly;  because,  where  the 
natural  waxes  have  not  been  cooked  out,  the  capillary  attraction 
of  the  central  canals  is  very  hard  to  overcome  with  rosin  size. 
Several  high-grade  mills  have  thoroughly  tried  out  this  practice, 
and  the}'  now  insist  that  all  rags  shall  be  cooked. 

Note. — IMost  of  the  fibrous  raw  materials  that  are  treated  in  the  paper 
mill  are  relatively  pure  cellulose,  which  is  practicalh'  unaffected  b}^  the 
relatively  mild  alkaline  cooking  liquors  and  the  weak  oxidizing  action  of 
bleach  solutions,  in  properly  conducted  mill  operations.  Cotton,  linen, 
hemp  and  jute  have  already  passed  through  operations,  incidental  to  the 
textile  and  cordage  industries,  which  have  largelj'^  removed  the  non-cellulose 
matter  originally  associated  with  the  fiber.  With  esparto,  straw,  bagasse, 
etc.,  the  treatment  is  necessarily  more  severe  than  with  textile  wastes;  but 
here  too,  the  recovered  cellulose  has  come  through  unaffected,  because  of  its 
wonderful  resistance  to  most  chemical  agents.  Some  of  the  more  important 
reactions  of  cellulose  have  been  mentioned  in  the  Section  on  Chemistry, 
Vol.  II,  and  the  Section  on  the  Properties  of  Wood,    Part  2,  Vol.  III. 

27.  Cooking  Liquor. — There  are  three  different  cooking  liquors 
in  general  use  in  cooking  rags:  the  liquor  made  with  caustic  lime; 
that  made  with  caustic  soda;  and  that  made  by  using  a  combina- 
tion of  caustic  lime  and  soda  ash.  Much  has  been  written  and 
said  as  to  the  advantages  of  an^^  one  of  these  processes  over  each 
of  the  other  two,  widely  divergent  opinions  have  been  expressed, 
and  two  investigators  reach  diametrically  opposite  conclusions. 
Such  being  the  case,  no  attempt  will  here  be  made  to  settle  this 
argument.  It  is  reasonably  certain,  moreover,  that  with  careful 
handling,  rag  pulp  (half-stuff)  that  is  of  excellent  qualitj^  can  be 
produced  with  any  one  of  these  cooking  liquors.  A  few  of  the 
points  usually  brought  up  in  a  discussion  of  this  subject  may  be 
of  interest,  however. 

28.  Lime  or  calcium  hydrate  attacks  the  natural  waxes 
energetically,  and  at  a  temperature  of  120°C.  (248°F.)  they  are 
saponified  in  less  than  two  hours.  Lime  also  attacks,  but  less 
readily,  the  oils  or  grease  that  may  be  present  in  the  rags.  The 
one  big  drawback  is  that  it  forms  calcium  salts,  most  of  which  are 
not  soluble,  and,  being  rather  sticky,  they  adhere  to  the  fiber. 


§1  RAGS  AND  RAG  FIBERS  19 

This  makes  the  washing  much  more  difficult,  since  the  small 
particles  of  lime  soap  must  be  carried  away  mechanically  in  the 
wash  water.  It  is  to  be  noted,  however,  that  this  is  not  an 
insurmountable  obstacle,  and  that  rags  cooked  with  lime  are 
being  washed  satisfactorily  all  over  the  country  every  day.  In 
addition,  it  is  to  be  remembered  that  lime  is  especially  adapted  to 
the  decomposition  of  a  large  number  of  dyestuffs  used  in  coloring 
cloth;  being  a  weak  alkali,  it  has  no  action  on  cellulose.  Conse- 
quently, it  is  used  very  widely  because  of  the  excellent  color 
obtainable  with  it.  Paper  makers  have  long  claimed  that  when 
lime  is  used  in  the  cooking,  the  resulting  product  does  not  have 
nearly  as  much  tendency  to  turn  yellow  as  is  the  case  when  caustic 
soda  or  soda  ash  is  used. 

29.  Caustic  soda  is  of  course  a  more  active  agent  than  lime.  It 
readih^  attacks  the  natural  waxes  and  the  oils  or  grease  that  may 
be  present  in  the  rags.  It  removes  glues  and  starch  sizings 
thoroughly,  and  it  forms  products  that  are  soluble  in  water  and 
which  are  easilj^  washed  out.  In  strong  solutions  and  at  high 
temperature,  the  cellulose  itself  may  be  acted  on.  The  writer's 
experience  has  been,  however,  that  it  does  not  attack  the  colors 
as  thoroughly  as  does  lime. 

30.  The  liquor  made  with  a  combination  of  Hme  and  soda  ash 
is,  of  course,  a  mixture  of  the  other  two,  with  a  certain  amount 
of  calcium  carbonate  in  suspension.  The  soda  present  increases 
its  causticizing  action,  and  it  more  effectually  removes  the  album- 
inous substances  that  may  be  present.  As  with  the  lime  alone, 
however,  the  resulting  products  are  all  insoluble,  since  any 
sodium  salt  formed  will  immediately  be  precipitated  by  the  lime, 
to  form  the  calcium  salt  and  caustic  soda.  Rags  of  dark  color 
and  very  dirty  rags  are  best  cooked  in  the  caustic  soda  or  lime- 
soda  ash  liquor.  When  lime  CaO  and  soda  ash  NaiCOa  are 
mixed  in  solution,  the  lime  first  forms  the  hydrate  Ca(0H)2, 
then  the  following  reaction  occurs: 

Ca(0H)2  +  NaoCOs  =  CaCOs  +  2NaOH 

The  CaCOa,  calcium  carbonate,  settles  out,  leaving  a  solution  of 
caustic  soda  NaOH. 

31.  The  tank  in  which  the  liquor  is  prepared  is  usually  so  situ- 
ated that  the  liquor  can  be  transferred  to  the  boiler  by  gravity, 
through  pipes;  it  usually  holds  the  quantity  required  for  one  cook 
or  one  "bleach."     If  lime  is  used,  the  tank  should  contain  an 


20     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

agitator,  similar  to  that  in  a  vertical  stuff  chest  (See  Section  on 
Beating  and  Refining);  and  the  resulting  liquor  should  be 
screened  before  going  to  the  boiler  or  to  storage,  in  order  to  make 
sure  that  all  lumps  are  removed.  When  lime  and  soda  ash  are 
used,  the  latter  should  first  be  dissolved,  then  the  necessary  lime 
should  be  added  and  well  stirred.  Let  settle,  and  draw  off 
through  a  strainer. 


BOILERS 

32.  Types  of  Boilers. — The  cut  and  dusted  rags  are  usually 
fed  into  the  boiler  by  a  chute,  which  feeds  into  the  manhole  at 
the  top.  In  the  rotary  boiler,  which  is  the  one  in  general  use, 
the  rags  must  be  packed  into  the  boiler  by  a  man  inside.     This 


Fig.  7. 

man  tramps  down  the  rags  and  stows  them  into  the  sections  of 
the  boiler  not  reached  by  the  chute.  He  should  wear  a  respirator 
to  keep  dust  from  his  lungs.  When  the  boiler  is  partly  filled, 
the  cooking  liquor  is  started  in,  for  when  the  rags  are  wet  they 
pack  much  more  closely.  It  is  essential  that  the  boiler  be  packed 
evenly  and  well  to  obtain  uniform  cooking.  The  liquor  pipe  is 
introduced  through  the  manhole  at  which  the  man  is  not  work- 
ing. An  open  vertical  pipe,  stuck  into  the  boiler,  assists  in  find- 
ing the  liquor  level. 

33.  The  boiler  in  general  use  in  this  country  is  the  cylindrical 
rotary  shown  in  part  section  in  Fig.  7.  This  is  a  large  cylindrical 
drum  (usually  about  8  feet  in  diameter  by  24  feet  in  length)  of 
such  dimensions  that  it  will  hold  about  5  tons  of  rags.  In  prac- 
tice, the  cooking  liquor,  made  up  with  water  if  necessary,  is 
brought  up  to  the  level  of  the  journals  Ti  and  T2  and,  in  some 


§1 


RAGS  AND  RAG  FIBERS 


21 


cases,  even  filling  the  boiler  two-thirds  full;  more  water  forms  as 
the  cooking  steam  condenses.  During  the  cooking  process,  this 
boiler  turns  at  the  rate  of  about  one  revolution  per  minute.  Note 
that  the  steam  is  admitted  directly  through  pipe  S  in  the  trunnion 
Ti,  and  is  distributed  by  the  different  lengths  of  pipe,  Ai,  A 2, 
usually  three,  opening  at  i,  |,  and  f  the  length  of  the  boiler.  In 
order  to  avoid  the  possibility  of  burning  the  rags,  nearly  all  of 
these  boilers  are  equipped  with  the  Kinne  valve.  This  is  a 
sleeve-type  valve,  situated  in  the  journal  at  K,  and  so  set  that 
steam  can  enter  the  distributing  pipe  only  when  the  pipe  is  in  a 


Fig.  8. 


position  below  the  cooking  liquor,  as  at  A 1.  However,  in  many 
rag  boilers,  steam  is  introduced  directly  at  the  trunnion  through 
a  perforated  plate.  Bi  and  B2  are  blow-off  pipes,  the  inlets  of 
which  are  covered  by  screen  S;  C  indicates  V-shaped  spikes,  to 
keep  rags  from  being  rolled  into  ropes;  Mi  and  Mo  are  manholes. 
At  the  end  of  the  cook,  the  liquor  is  drained  or  blown  off  through 
Bi  and  B2',  it  is  not  profitable  to  recover  the  chemicals  in  it. 

When  the  cooking  operation  is  finished,  the  steam  is  turned  off 
and  the  boiler  is  stopped,  with  the  valves  Bi  and  Bo  at  the 
bottom  in  position  to  connect  with  the  blow-off  pipes;  this  con- 
nection is  made,  and  the  valve  is  opened.  The  steam  pressure 
blows  off  the  boiling  hquor,  which  carries  with  it  large  amounts 
of  insoluble  material  in  suspension.     When  the  cook  is  thoroughly 


22     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

blown,  the  manholes  are  opened,  and  the  boiler  is  rotated  as  long 
as  rags  fall  out  readily;  then  it  is  brought  to  a  position  such  that 
the  rags  may  be  pulled  out  by  the  workmen  (using  long-handled 
2-prong  hooks)  into  cars  or  onto  the  floor,  to  drain. 

34.  A  boiler  of  the  same  general  type,  largely  used  in  England 
and  Europe,  and  somewhat  on  this  continent,  is  the  revolving 
spherical  boiler  shown  in  Fig.  8.  This  boiler  is  set  on  trunnions, 
and  is  operated  on  the  same  principle  as  the  cylindrical  rotary; 
it  finds  some  favor  in  cooking  straw.  Its  only  advantage  is  that 
higher  steam  pressures  can  be  carried  in  it;  it  also  empties  a 
little  faster  than  the  cylindrical  form  of  boiler,  but  has  less 
capacity. 

-E 


'»V» 


Fig.  9. 


The  boiler  is  turned  by  means  of  the  worm  gear  and  pulley 
mechanism  W.  Steam  enters  at  S,  and  is  distributed  by  the 
perforated  plate  P;  lye  enters  at  L,  or  through  the  manhole;  V  is 
an  air  vent ;  /?  is  a  blow-off  valve ;  A^  is  a  perforated  plate ;  and  M 
is  a  manhole,  for  charging  and  emptying. 

35.  Another  cooker  that  may  be  of  interest  is  the  Mather  kier, 
Fig.  9,  which  is  an  adoption  into  paper  making  from  the  textile 
industry.  It  has  been  applied  to  the  cooking  of  rags  for  paper  mak- 
ing in  England,  and  the  results  reported  seem  to  merit  attention. 
The  results  obtained  are  given  in  a  report  by  Cross  and  Bevan. 
"Its  dimensions  are  8  feet  long  by  7  feet  in  diameter,  and  it  is 
adapted  to  hold  two  wagons  Ai,  A 2,  of  special  design,  which  are 
run  into  the  kier  on  tracks  B.     In  order,  however,  to  economize 


§1  RAGS  AND  RAG  FIBERS  23 

time,  six  wagons  are  employed,  four  being  either  filled  or  washed, 
while  the  other  two  contain  rags  in  process  of  treatment  in  the 
kier.  The  cut  and  dusted  rags  are  delivered  automatically  from 
a  chute,  directly  into  the  wagons.  The  running  of  the  wagons 
into  the  kier  and  the  closing  of  the  door  C  occupy  only  some  2  or  3 
minutes.  The  door  is  lifted  by  means  of  chain  D  passing  over 
pulley  E  to  chain  drum  F;  the  latter  is  attached  to  worm  and  worm 
wheel  G,  which  is  operated  by  hand  wheel  H.  The  door  slides 
between  frames  J,  which  are  wedge  shaped ;  thus  the  farther  the 
door  slides  down,  the  tighter  the  joint  between  it  and  the  body  of 
cooker.  As  soon  as  door  C  is  closed,  the  rags  are  saturated  with 
caustic-soda  solution,  which  is  delivered  through  sprays  K,  from 
a  tank  above  the  kier,  and  is  circulated  by  means  of  a  centrifugal 
pump  L.  Steam  is  turned  on  until  the  pressure  reaches  10  pounds, 
and  the  process  is  continued  for  from  2  to  3  hours,  according  to  the 
nature  of  the  material.  The  steam  is  blown  off,  which  occupies 
about  15  minutes,  the  door  is  opened,  the  wagons  are  removed,  and 
another  pair  run  in,  the  three  latter  operations  occupying  only 
10  minutes.  The  rags,  after  being  withdrawn  from  the  kier  are 
washed  by  flowing  water  on  the  top  of  the  wagons.  This  kier 
is  capable  of  doing  at  least  40  tons  of  rags  per  week,  and  it  is 
adaptable  to  all  classes  of  rags. " 

36.  Among  the  advantages  claimed  for  the  kier  are:  (a)  A 
notable  improvement  in  the  color  of  the  rags,  both  before  and 
after  bleaching;  (6)  economy  in  washing  time;  (c)  saving  in 
steam;  {d)  improved  strength  of  fiber;  and  (e)  an  enormous 
saving  in  space — one   kier  doing   the   work   of   several   boilers. 

37.  The  possibilities  of  washing  the  rag  with  hot  water  before 
its  removal  from  the  boiler  are  worth  careful  thought.  This 
procedure  results  in  a  brighter-colored  stock  and  a  considerable 
saving  in  washing  time  in  the  washing  engine,  besides  making 
use  of  the  heat  in  the  boiler  and  rags. 

38.  Cooking  with  Lime. — Caustic  lime  alone  is  widely  used  on 
this  continent  for  cooking  new,  white  cuttings.  In  the  mills 
making  the  highest  grades  of  writing  paper,  where  such  grades 
of  rags  as  hoisery  clips,  white  shirt  cuttings,  etc.,  are  being  used, 
the  almost  universal  practice  is  to  employ  lime  alone  for  the 
cooking.  These  rags  are  alwa.ys  clean,  and  thej^  do  not  need  the 
severe  causticizing  action  of  caustic  soda,  which  has  a  tendency 
to  make  rag  stock  yellow.     The  excellent  color  produced  by 


24     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

cooking  with  lime  is  another  factor  determining  its  use  for  that 
particular  purpose.  Lime,  also,  is  the  cheapest  alkali.  The 
usual  practice  in  cooking  this  grade  of  rag  would  be  as  follows : 

For  5  tons  of  rags  600  pounds  of  lime  would  be  used.  The  pressure 
carried  in  the  boiler  would  be  30  to  40  pounds,  and  the  cooking  time  10  to 
12  hours. 

In  using  hme  there  is  the  question  of  just  what  kind  of  lime 
it  should  be.  Careful  thought  points  to  the  conclusion  that 
there  is  but  one  kind  of  lime,  the  use  of  which  is  admissible, — 
that  is  a  straight  calcium  lime.  In  the  manufacturing  of  sulphite 
pulp,  a  lime  containing  a  high  percentage  of  magnesium  is  sought 
after  and  used  with  good  results.  For  a  rag  mill  no  such  advan- 
tage holds  and  the  presence  of  any  considerable  amount  of  magne- 
sium makes  that  part  of  the  lime  almost  useless  for  cooking  rags. 
Magnesium  hydroxide  is  relatively  even  more  insoluble  than 
calcium  hydroxide  and  its  action  is  almost  negligible. 

Note. — The  time  required  varies  with  different  lots  of  rags,  according  to 
color,  dirtiness,  etc.,  and  must  be  determined  by  experience.  Cooking  too 
long  wastes  time,  steam  and  sometimes  fiber.  Too  short  a  cook  means 
more  trouble  in  washing,  excessive  bleach  consumption,  and  probably  a 
harsh  stock  for  the  beater. 

39.  Cooking  with  Lime  and  Soda  Ash. — The  next  general 
class  of  rags  to  be  considered  includes  new  cuttings  of  unbleached 
or  colored  material  such  as  blue  overall  cuttings,  unbleached 
shoe  cuttings,  shirt  cuttings,  etc.  For  cooking  this  type  of  rag, 
a  combination  of  lime  and  soda  ash  is  generally  used.  When 
cooking  these  rags,  it  is  advisable  to  keep  the  chemicals  fairly 
high,  to  take  care  of  the  fragments  of  cotton  seed  hull,  so  often 
found.  The  paper  maker  calls  them  "shives,"  and  they  must 
be  thoroughly  cooked  to  prevent  their  appearance  in  the  finished 
sheet  of  paper.  The  usual  treatment  of  this  type  of  rag  is  about 
as  follows: 

For  5  tons  of  rags,  use  1000  or  1200  pounds  of  lime  and  300  to  400  pounds 
of  soda  ash.  The  pressure  would  be  carried  at  30  to  40  pounds,  and  the 
cooking  time  would  be  about  15  hours. 

40.  Cooking  Old  Whites. — Old  rags  are  divided  roughly  into 
two  types  or  classes;  one  of  which  is  the  type  known  as  old 
whites.  This  class  would  include  the  No.  1  whites,  the  No.  2 
whites,  and  the  street-soiled  whites.  There  is  some  variation  in 
the  general  practice  with  regard  to  these  rags.     Many  of  the 


§1  RAGS  AND  RAG  FIBERS  25 

mills  use  lime  alone  on  the  better  grades,  while  others  use  a 
combination  of  lime  and  soda  ash.  An  average  procedure  might 
be  this: 

For  5  tons  of  rags,  use  600  pounds  of  lime  and  50  pounds  of  soda  ash; 
cook  at  25  pounds  pressure  for  12  hours. 

This  rag  has  usually  been  washed  many  times  before  it  comes 
to  the  paper  mill,  and,  as  a  result,  the  natural  waxes  and  resins 
of  the  fiber  have  already  been  pretty  well  removed.  The  purpose 
of  the  cooking,  then,  is  to  remove  the  oils,  grease  and  dirt  that 
may  be  present.  This  being  the  case,  it  would  seem  that  the 
addition  of  a  small  amount  of  soda  ash  to  the  cooking  liquor  would 
perhaps  be  the  better  practice. 

41.  Cooking  White  and  Colored  Cotton  Mixtures. — The  other 
class  of  old  rags  is  that  in  which  there  is  a  mixture  of  white  and 
colored  cottons,  as  twos  and  blues,  thirds  and  blues,  etc. 

In  cooking  this  type  of  rag,  both  lime  and  soda  ash  are  used. 
The  lime  helps  materially  in  producing  a  good  white,  and  the 
soda  ash  is  needed  to  bring  up  the  causticity  of  the  cooking 
liquor  to  a  point  where  it  will  more  efficiently  attack  the  dirt  and 
grease  present.  The  usual  treatment  for  this  type  would  be  as 
follows : 

For  5  tons  of  rags,  use  1200  pounds  of  Ume  and  about  150  pounds  of  soda 
ash.     Cook  at  25  to  30  pounds  pressure  for  12  to  15  hours. 

42.  Cooking  Linens. — In  the  cooking  of  linen  rags,  as  in  the 
case  of  cotton,  no  general  rule  can  be  laid  down,  as  very  much 
depends  on  the  particular  character  of  rags  to  be  cooked.  The 
cooking  liquor  is  either  caustic  soda  or  a  combination  of  soda 
ash  and  lime.  For  a  new,  white  linen,  free  from  shives,  the 
cooking  treatment  is  rather  mild;  2%  of  caustic  soda,  with 
a  pressure  of  about  20  pounds  for  6  hours,  would  cook  the  rags 
thoroughly. 

For  old  linens  or  new  gray  linens,  which  are  quite  likely  to 
contain  shives,  a  fairly  strong  liquor  of  lime  and  soda  ash 
is  needed.  Here  the  pressure  would  be  advanced  to  30  to  35 
pounds,  and  the  time  to  10  or  12  hours. 

Note. — Linen  is  composed  of  the  bast  fibers  of  the  flax  plant, 
Linum  usitatissimum.  The  plant  yields  about  8  %  of  fiber,  which  is  sepa- 
rated by  retting  and  is  then  known  as  flax.  The  ultimate  fibers  are  6  to 
60  mm.  long,  and  are  0.012  to  0.026  mm.  wide,  the  average  ratio  of  length  to 


26     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

width  being  about  1200:1.  The  fibers  are  thin-walled  tubes,  with  thickened 
places  or  knots  at  intervals;  the  ends  are  tapered,  the  walls  rather  trans- 
parent, and  the  canal  is  small.  Two  samples  of  Belgian  flax  have  been 
found  to  contain  81.99%  and  70.55%  cellulose. 

43.  Use  of  Caustic  Soda. — In  England  and  on  the  continent 
of  Europe,  caustic  soda  is  largel}'  used  in  cooking  all  grades  of 
rags,  lime  being  recommended  onlj^  for  the  very  cheapest. 
The  amount  of  caustic  soda  used  varies  from  1%  to  4%  or  5%  of 
the  weight  of  the  rags,  depending,  of  course,  on  the  nature  of  the 
rags  to  be  cooked.  It  is  well  adapted  for  rags  containing  albu- 
minous and  starch  sizings,  and  it  readily  attacks  oil,  grease  and 
dirt.  The  rags  are  easily  washed,  and  they  make  excellent  rag 
pulp.  It  is  generally  recognized,  however,  that  cooking  with 
lime  will  give  a  pulp  of  better  color.  If  the  question  of  cost  is  to 
be  considered,  lime  is  cheaper  b}'  far  than  the  caustic  soda. 

44.  Variations  in  Cooking  Practice. — To  date,  there  is  no 
definite  evidence  as  to  the  comparative  strengths  of  rags  cooked 
with  lime  as  against  those  cooked  with  caustic  soda.  The 
fact  that  both  processes  are  in  excellent  repute  leads  to  the  belief 
that  no  great  difference  will  be  found  one  way  or  the  other. 
There  is  considerable  variation  in  practice  among  the  different 
mills  with  regard  to  the  cooking  pressure  and  the  duration  of 
the  cook.  In  some  mills,  the  practice  is  to  cook  at  a  high  pressure 
and  for  a  short  length  of  time,  while  in  others,  this  practice  is 
reversed.  It  is  very  seldom  necessary  to  exceed  a  pressure  of  40 
pounds  or  a  cooking  time  of  18  hours. 

Whatever  the  practice  of  the  particular  mill,  it  is  generalh- 
agreed  that  rags  should  be  thoroughly  cooked.  Well-cooked 
rags  wash  easil}',  bleach  easily,  and  produce  a  whiter  pulp. 
They  respond  better  to  treatment,  and  produce  better  and  more 
nearly  uniform  paper.  It  is  a  mistake  to  undercook  rags,  with 
the  idea  that  the}-  will  produce  a  stronger  or  more  durable  paper. 


WASHING  RAGS 

45.  The  Washing  Engine. — Fig.  10  is  a  plan  and  longitudinal 
section  typical  of  the  Hollander  type  of  washing  engine,  which 
is  most  common.  It  consists  of  an  open  tub  A,  in  which  the  rags 
and  water  circulate.  The  circulation  is  maintained  by  the  roll  R, 
which  throws  the  rags  over  the  back-fall  B.     In  front  of  the  roll, 


§1 


RAGS  AND  RAG  FIBERS 


27 


shown  in  section,  is  the  button  catcher  C;  this  is  a  recess  in  the 
floor,  covered  by  a  metal  grid,  and  its  purpose  is  to  catch  any 
buttons,  metal,  sand,  etc.  that  may  still  be  in  the  stock.  In 
many  cases,  a  second  button  catcher  is  installed  just  behind  the 
back-fall.  The  roll,  or  fly,  bars  J  are  set  about  3  inches  apart  in 
notches  in  the  circumferences  of  three  disks,  keyed  to  shaft  S,  and 
the  spaces  are  filled  with  wedges  of  wood.  The  bed  plate  P  is  made 
up  of  metal  bars  interspaced  with  wood.     For  a  washing  engine, 


Fig.  10. 

bed  plate  should  be  of  the  type  that  the  paper  maker  calls  a  slow 
the  plate,  say  \  or  y\  inch  bars  and  \  or  yV  inch  wood.  The 
roll,  making  90  to  100  r.p.m.,  or  even  120  r.p.m.,  draws  the 
rags  over  this  bed  plate  and  draws  them  out;  i.e.,  unravels  the 
weave.  At  some  point  like  V  (shown  in  the  plan)  is  a  valve  for 
dumping  the  washer.  L,  L,  are  the  lighter-bars  (levers),  on  which 
the  roll  bearings  rest,  and  by  means  of  which  the  roll  is  raised 
or  lowered  through  the  action  of  a  worm  gear  and  screw,  described 
in  detail  in  the  Section  on  Beating  and  Refining.  A  hydrant, 
situated  at  H,  is  the  means  of  furnishing  water  to  the  washer. 
For  washing  oily  rags,  where  much  foam  is  produced,  the  foam 
may  be  skimmed  off  by  a  strainer  of  coarse-mesh  wire  M,  which 


28     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

allows  the  foamy  water  on  top  to  pass  out  the  outlet  N,  retaining 
the  rags.     W  is  the  washing  cylinder  described  in  Art.  46. 

46.  Fig.  11  shows  the  principle  and  construction  of  a  washing 
cylinder.  Two  octagonal  wooden  heads  Ai  and  A  2  are  carried 
by  the  shaft  B;  Ai  is  fastened  to  the  shaft  by  a  spider,  which 
gives  an  outlet  through  the  sleeve  C.  Both  heads  arc  slotted 
radially,  as  at  D,  from  the  center  to  each  vertex  (corner),  and 
also  from  each  vertex  perpendicular  to  these  slots,  as  at  E. 
Boards  F  are  slipped  into  slots  D,  meeting  at  the  center,  and 
ending  flush  with  slots  E.  Boards  G  fit  slots  E,  and  are  planed 
at  the  edge  flush  with  the  sides  of  the  octagons,  leaving  a  space 


Fig.  11. 

H  for  water  to  enter  as  the  drum  turns.  A  fillet  K  deflects  the 
water  to  the  outlet  C  as  each  pocket  rises.  Wooden  gratings, 
covered  with  copper  or  bronze  wire  screen  of  50-60  mesh,  are 
screwed  to  the  heads  and  complete  the  cylinder;  the  screen 
prevents  much  loss  of  fiber,  though  some  short  ones  get  through. 
The  cylinder  W  (Fig.  10,  which  also  see)  turns  at  the  rate  of 
about  12  r.p.m.,  being  lowered  by  a  ratchet  so  that  a  gear  E  on 
shaft /^engages  a  pinion  K  made  fast  to  a  pulley  D,  which  is  driven 
by  a  belt  from  the  roll  spindle  *S.  A  washing  engine  may  carry 
from  one  to  four  of  these  drums,  as  may  be  necessary. 

Another  type  of  washing  apparatus  is  shown  in  the  Section  on 
the  Treatment  of  Waste  Papers. 

47.  After  the  rags  leave  the  boiler,  they  are  usually  allowed 
to  stand  in  the  cars  for  24  hours.  Evidence  has  shown 
that  by  standing  in  this  wa}^,  the  dirt  is  more  readily  washed 
out,  and  a  better  color  is  obtained  on  the  half-stuff.  Before  the 
rags  are  furnished  to  the  washer,  some  sort  of  a  foam  killer 
should  be  added,  especially  in  the  case  of  rags  cooked  with  soda 
ash    or    caustic    soda.     A    pint    of   kerosene   oil  to  each  300 


§1  RAGS  AND  RAG  FIBERS  29 

pounds  of  rags  is  as  effective  as  most  of  the  prepared  or  patented 
foam  killers. 

48.  The  Washing  Process. — The  washing  engine  is  partly 
filled  with  water,  the  roll  taken  up  well  off  the  bed  plate,  and  the 
rags  furnished,  meanwhile  adding  water  gradually.  Soon  after 
the  furnishing  is  completed,  the  washing  cylinder  is  let  down, 
and  the  hydrant  valve  is  so  regulated  as  to  give  all  the  water  the 
cylinder  can  take  out.  For  the  first  hour,  the  engine  should 
have  plenty  of  water,  and  the  roll  should  be  kept  well  off  the 
plate,  so  that  it  is  just  brushing  the  rags.  Putting  the  roll  down 
too  soon  will  rub  the  dirt  into  the  fibers,  and  the  result  will  be 
poor  color.  After  an  hour's  washing,  the  color  will  usually  be 
such  that  the  washerman  can  begin  to  bring  down  his  roll  and 
take  the  fiber  out  of  the  rags.  This  must  be  a  slow  process,  and 
the  roll  should  be  lowered  gradually  and  often  instead  of  vice  versa. 
As  the  washing  progresses,  the  amount  of  wash  water  may  be 
reduced,  especially  if  it  is  necessary  to  supply  a  maximum  to 
another  washer  that  has  just  been  furnished.  The  rags  are 
washed  until  the  effluent  is  practically  clear,  and  until  the  fibers 
are  well  drawn  out  of  the  rags.  Care  must  be  taken  not  to  cut 
the  fibers,  for  long  half-stuff  is  much  better  than  short  half -stuff ; 
the  beaters  can  shorten  the  fibers,  but  can't  make  them  longer. 

49.  Discussion  of  Washing. — An  important  consideration  in 
the  paper-making  process  is  the  water.  Cellulose  readily  absorbs 
organic  coloring  material  from  it,  and  becomes  yellowish;  iron 
is  sure  to  cause  discoloration  in  white  or  delicately  tinted  papers. 
One  hundred  gallons  a  minute  is  a  very  reasonable  amount  to 
use  in  a  thousand-pound  washing  engine.  This  means  a  lot  of 
water;  and  if  organic  coloring  materials  are  present  in  quantity, 
there  is  a  marked  effect  on  the  color  of  the  half-stuff.  Clean, 
colorless  water  is  a  necessity  where  fine  papers  are  made. 

The  time  given  for  washing  the  various  grades  or  classes  of 
rags  runs  from  5^  or  6  hours  to  perhaps  14  hours,  in  a  few  extreme 
cases.  In  the  case  of  linens,  white  shirt  cuts,  hoisery,  etc.,  the 
length  of  treatment  is  determined  by  the  time  needed  properly 
to  draw  out  the  fiber;  8  to  12  hours  covers  the  range  in  this  class. 
For  such  rags  as  overall  cuttings  and  the  like,  8  hours  is  a  fair 
length  of  time.  In  the  case  of  old  rags,  the  time  needed  to  wash 
them  clean  is  an  important  factor.  For  thirds  and  blues,  0  hours 
is  the  usual  time. 


30     PREPARATION  OF  RAG  AND  OTHER  FIBERS      §1 

In  all  the  above  cases  one  hour  is  allowed  for  bleaching  after 
the  washing  itself  is  finished,  and  bleaching  is  the  next  subject 
to  be  considered  here. 


QUESTIONS 

(1)  Name  the  three  kinds  of  Hquor  used  for  cooking  rags,  and  give  the 
molecular  formulas  of  the  chemicals  in  each. 

(2)  Mention  an  advantage  and  disadvantage  of  each  kind  of  cooking 
liquor. 

(3)  How  is  cooking  liquor  prepared? 

(4)  What  kinds  of  rags  are  best  cooked  with  (a)  lime?     (h)  lime  and  soda 
ash?     (c)  caustic  soda? 

(5)  Why  should  rags  be  thoroughly  cooked? 

(6)  (a)  What  are  the  principal  features  of  the  washing  engine?     (6)  State 
the  function  of  each. 


BLEACHING,  DRAINING,  AND  LOSSES 


BLEACHING 

50.  Theory  of  Bleaching. — In  the  process  of  bleaching,  the 
impurities  that  cover  up  the  natural  whiteness  of  the  cotton  fiber 
are  oxidized  and  removed;  the  fiber  itself  will  stand  the  action  of 
reasonable  bleaching  without  being  impaired. 

While  there  are  many  possible  bleaching  agents,  chlorine  or  a 
chlorine  salt  is  the  most  economical,  and  is  the  one  generally 
used.  The  bleaching,  or  oxidizing,  is  not  due  primarily  to  the 
action  of  the  chlorine,  but  rather  to  the  fact  that  the  chlorine 
reacts  with  water,  liberating  oxygen.  This  oxygen  attacks  and 
destroys  nearly  all  coloring  materials  and  impurities,  changing 
them  to  colorless  or  soluble  substances,  and  restores  to  the  cellu- 
lose its  natural  color.  A  slight  yellow  color  can  be  compensated 
for  by  proper  dye-stuffs.  Taking,  for  example,  the  case  of  bleach- 
ing powder,  which  is  most  used,  this  reacts  somewhat  as  follows  • 
(See  Sections  on  Elements  of  Chemistry,  Vol.  II,  and  Bleaching  of 
Pulp,  Vol.  Ill):  In  solution  in  water, 

2CaCl(OCl)-^Ca(OCl)2  +  CaCla; 
then, 

Ca(0Cl)2  +  2H20-^Ca(OH)2  +  2HC10, 
2HC10->2HC1  +  20(nascent), 
Ca(0H)2  +  2HCl->CaCl2  +  2H2O. 


§1  RAGS  AND  RAG  FIBERS  31 

The  final  products  of  the  bleaching  powder  are,  then,  calcium 
chloride  and  oxygen  in  the  nascent  state.  The  oxygen  unites 
with  the  impurities  to  form  less  objectionable  compounds.  The 
action  of  liquid  chlorine  is  very  much  the  same ;  the  final  products 
being  oxygen  and  hydrochloric  acid.  The  intermediate  reaction 
is: 

H2O  +  CI2  =  HCl  +  HCIO. 

Soda  ash  is  usually  added  to  neutralize  the  hydrochloric  acid  so 
formed,  giving  NaCl  and  H2O  and  CO2.  It  is  to  be  noted  that 
acids  are  injurious  to  the  fiber,  and  that  they  affect  some  coloring 
matters. 

51.  To  get  the  largest  yields  in  the  preparation  of  bleach  liquor 
from  bleaching  powder,  special  care  must  be  given  to  the  process. 
Yields  of  85  %  to  95  %  of  the  actual  available  chlorine  present  are 
possible,  but  yields  of  60%  to  80%  are,  unfortunately,  rather 
common.  One  of  the  first  things  to  determine  is  the  strength 
to  which  the  liquor  shall  be  made  up.  A  few  minutes  thought 
will  prove  that  the  lower  the  Baume  test  of  the  liquor  the  more 
water  may  be  used  in  washing  the  sludge  and  the  higher  will 
be  the  yield.  On  the  other  hand,  the  Baume  test  must  not  be 
run  too  low,  because  of  the  greatly  increased  storage  facilities 
needed.  A  liquor  testing  4°  Baume  is  perhaps  the  most  econom- 
ical. The  sludge  remaining  in  the  settling  tank  should  always 
be  washed  once,  perhaps  twice;  the  latter  is  usually  possible 
only  when  the  liquor  that  results  from  the  second  washing  can 
be  used  with  new  bleaching  powder,  to  prepare  the  strong  liquor. 

52.  Preparation  of  Bleach  Liquor. — The  method  of  preparation 

of  bleach  hquor  is  briefly  as  follows : 

The  powder  and  either  wash  water  or  fresh  water  are  put  into 
a  tank  having  a  mechanical  agitator,  like  an  ice-cream  freezer, 
or  like  the  vertical  stuff  chest  shown  in  the  section  on  Beating  and 
Refining.  The  whole  is  mixed,  and  the  lumps  are  thoroughly 
broken  down.  This  mixture  is  then  pumped  to  the  settling  tank, 
where  as  much  w^ater  as  is  needed  is  added.  The  minimum 
settling  time  for  reasonable  yields  is  24  hours,  and  wherever 
possible,  48  hours  should  be  allowed.  This  liquor  may  then  be 
run  off  from  the  sludge  into  the  storage  tank,  using  either  wash 
liquor  or  water,  as  the  case  may  be,  to  bring  it  to  the  required 
degree  Baurn^,  i.e.  the  desired  chlorine  content. 


32     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

Extreme  care  must  always  be  taken  to  see  that  the  liquor  in 
the  storage  tank  is  clear,  which  means  that  a  high  calcium  lime 
should  be  used  for  making  the  bleaching  powder.  A  bleach 
liquor  that  is  turbid,  due  to  carelessness  in  running  from  the 
settling  tank,  will  lose  much  of  its  action  in  the  washer. 

53.  The  Bleaching  Process. — Before  adding  the  bleach  Hquor 
to  the  washing  engine,  the  roll  should  be  taken  up  off  the  plate, 
the  wash  water  turned  off,  the  excess  water  removed,  and  the 
washing  cylinder  raised.  The  bleaching  liquor  may  then  be 
slowly  added.  The  usual  practice  in  American  mills  is  to  add 
an  acid  substance  as  an  accelerator,  after  the  bleaching  liquor  is 
in;  this  must  be  done  with  great  care.  A  few  pounds  of  alum  to 
each  washer  makes  a  very  good  accelerator,  and  is  safer  than  acids, 
such  as  acetic  acid,  but  especially  HCl  and  H2SO4.  It  assists  in 
converting  the  Ca(0Cl)2  to  HCIO.  The  use  of  an  antichlor 
is  common  in  neutralizing  occasional  excess  of  bleach;  but  it 
cannot  be  unqualifiedly  recommended,  because,  in  most  cases, 
the  cure  is  as  bad  as  the  disease.  Sodium  hyposulphite,  sodium 
sulphite,  and  calcium  sulphite  have  all  been  used,  usually  in  the 
beater,  and  many  others  have  been  suggested  and  tried.  The 
use  of  antichlor,  however,  is  becoming  more  and  more  the  excep- 
tion in  the  bleaching  of  rags.  The  bleaching  may  also  be 
hastened  by  warming  the  stock.  This  may  be  done  by  blowing 
in  steam  before  adding  the  bleach;  the  temperature  should  not 
exceed  100°F. 

After  the  rags  have  been  brought  to  color,  the  excess  chlorine 
should  be  washed  out  by  lowering  the  washing  cylinder  and 
turning  in  fresh  water.  A  very  slight  excess  may  be  left  to 
spend  itself  in  the  drainer. 

There  is  a  further  method  of  washing  the  excess  chlorine  from 
the  rags,  which  gives  excellent  results.  When  the  bleaching  is 
nearly  complete,  the  rags  are  dropped  into  the  drainer.  After 
the  drainer  is  filled,  12  hours  is  allowed  for  the  rags  to  come  up  to 
color.  At  that  time,  two  or  three  washers  of  water  are  put  down 
on  the  drainer  of  half  stock. ^  This  process  is  repeated  12  hours 
later.     In  this  way,  practically  all  traces  of  chlorine  are  removed. 

54.  Use  of  Liquid  Chlorine. — During  the  last  few  years,  the 

use  of  liquid  chlorine  for  bleaching  rags  has  been  demonstrated 

as  a  commercial  possibility;  and  it  now  seems  likely  that  within 

1  Half  stock  or  half-stuff  is  defibered  raw  material  that  is  ready  for  the 
beater.     See  Art.  27. 


il 


RAGS  AND  RAG  FIBERS 


33 


the  next  five  years  its  use  will  become  quite  general,  since  it  is 
both  convenient  and  more  economical  than  bleaching  powder. 

The  only  apparatus  required  in  order  to  use  it  is  that  for  trans- 
ferring it  and  measuring  it  into  the  washing  engine.     A  scale 


Chfck  Va»ve 


Compression  f  hambcr ' 
VacuunA  Relief  Line- 
Solution  Back  Pressure  Gauge 
Manometer  For  Soltition  Meter- 
Solution  Control  Valve-^^ 


Solution  Line  To  Bleaching  Tanks 
Chlorine  Back  Pressui-e  Gaugr 
Chlorine  Control  \  alve 
Manonictor  For  Chlorine  Meter 
Chloiine Shut  Off  Valve 

Chlorine  Blow  Off  Line--- --■ 

Steani  Exhaust  Line — --• 

Chloi'ine  Prcssui'c  Reducing  Valve 
iTank  Pressure  Cau^c 
Manifold 


I  "Water  Pressure  Redxieing  V^ahe 

■-  Stiaincr 

Chlorine  Cylindci's 
^--Cold  Water  Supply  Line 
^  Blo-H'cr 


ELEVATION 


Thermostat     - 
Automatic  Steam  Valvc^ 

Waste  Line 

Steani  Supply  Line ' 

Steam  Control  Valve  IbManifold 
<^irculaiin^  Pipe 
Evapoi-ator  Tank 
Steam  Shut  Off  Valve 
Overflow 


for  weighing  the  container,  and  an  injector,  accomplishes  this 
readily.     Fig.  12  shows  a  diagram  of  a  typical  installation. 

55.  In  using  liquid  chlorine  it  has  been  found  that  the  white 
produced  on  the  half-stuff  has  a  slightly  reddish  tinge,  which 
replaces  the  shghtly  yellowish  tinge  that  is  produced  with  bleach- 
ing powder.     This,  however,  can  be  easily  corrected  in  coloring. 


34     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

Soda  ash  is  generally  added,  to  neutralize  the  HCl  formed  in  the 
bleaching  reaction;  otherwise,  the  acid  would  attack  the  fiber, 
the  steel  of  the  beater  roll,  and  the  paper  machine.  Experience 
has  shown  that  a  pound  of  chlorine  gas  will  do  the  work  of  about 
10  pounds  of  bleaching  powder,  which  may  be  figured  roughly 
as  one-third  chlorine;  it  is  always  ready  for  use,  and  no  mixing 
and  settling  tanks  are  required. 

56.  Amount  of  Bleach  Needed. — The  amount  of  bleaching 
powder  required  in  bleaching  rags  naturally  varies  considerably, 
both  with  the  color  of  the  rag  before  bleaching  and  the  color  to 
which  it  is  desired  to  bring  the  rag  half  stock.  For  new  white 
cuttings,  the  amount  of  bleach  used  is  about  1%,  or  10  pounds  of 
bleaching  powder  in  solution  for  a  thousand-pound  washer.  At 
the  other  extreme,  for  such  rags  as  Thirds  and  Blues,  from  5% 
to  6%  of  bleaching  powder  is  generally  used. 


DRAINING 


57.  The  Drainer. — When  the  half-stuff  in  the  washing  engine 
has  come  up  to  color  and  the  chlorine  is  washed  out,  the  valve 


p. 


^1 


-ile, 


^ 


Vft 


Kt 


H 


4-C 


0 


T^ 


S 


Fig.  13. 


in  the  bottom  of  the  engine  is  lifted  and  the  last  of  the  material 
is  raked  down  to  the  valve,  whence  it  flows  into  the  drainer 
through  a  system  of  pipes  and  valves.  Fig.  13.  Di,  D^,  etc.  are 
drainers.  The  stock  comes  down  in  pipe  P.  To  fill  any  drainer, 
as  7)0,  all  preceding  side  pipes.  Pi,  etc.,  are  closed  by  valves  Gi, 


§1 


RAGS  AND  RAG  FIBERS 


35 


etc.;  Go  is  opened  and  the  main  pipe  closed  as  at  iv>,  preventing 
stock  for  drainer  Do  from  filling  the  remainder  of  P  and  later 
passing  to  another  drainer.  The  pipe  line  is  often  a  plain  wood 
box.  Sometimes  the  gates  Gi,  G2,  etc.  arc  hung  so  as  to  swing 
across  either  the  main  channel  P  or  the  side  channels,  Pi,  P2,  etc., 
thus  eliminating  gates  Ki,  K2,  etc. 

The  purpose  of  the  drainers  is  well  expressed  in  the  name;  i.e., 
they  allow  the  water  to  drain  from  the  stock  and  to  take  solul)le 
impurities  with  it.     In  addition 


I 


1 


■^  s\\S\\\i^yk\\NK\\N\\\^\^^^^         ^ 


i 


Fig.  14. 


to  this,  the  drainer  also  provides 
for  rag  half-stuff,  storage  suf- 
ficient to  take  care  of  the 
necessary'  variation  between  the 
consumption  and  production. 

The  drainer  is  a  small  room, 
which  may  be  20  feet  long  by  8 
to  10  feet  wide,  and  about  as 
high.  It  is  of  masonry  con- 
struction throughout,  except 
for  a  wooden  door  A  (Fig. 
14).  This  door  is  an  opening 
in  the  front  of  the  drainer ;  it  is 
about  3  feet  square,  and  about 
3  feet  from  the  floor.  Fig.  14 
shows  how  the  floor  of  the 
drainer  is  constructed.  When  the  special  tile  (perforated  with 
holes  wider  at  the  bottom)  is  used,  the  false  floor  is  laid  on  con- 
crete, with  a  slight  slope  to  a  main  drain. 

58.  Time  that  Stock  Is  in  Drainer, — Rag  stock  should  usually 
be  left  in  the  drainers  for  two  to  three  weeks  for  best  results. 
It  is  possible  to  use  the  stock  in  a  shorter  time,  and,  in  the  excep- 
tional case,  stock  may  stay  in  the  drainer  for  several  months.  In 
the  latter  case,  however,  it  is  usually  advisable  to  freshen  the 
stock  by  letting  a  washer  of  water  and  })leaching  liquor  down  on 
top  of  it.  This  helps  materialh'  in  the  subsequent  use  of  the 
stock. 

The  possibilities  of  washing  the  stock  in  the  drainer  by  putting 
down  washers  of  water  on  it,  have  been  discussed  full}-  above, 
and  the  subject  need  not  be  given  further  consideration  here. 
Care  must  be  taken  that  as  each  kind  of  stock  comes  through 
from  the  boiler,  a  drainer  is  empty  and  clean,  ready  for  it. 


36     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

59.  Possible  Use  of  Wet  Machine. — It  has  often  seemed  that 
it  might  be  possible  to  adapt  a  wet  machine  (used  for  de-watering 
wood  pulp,  as  described  in  the  Section  on  Treatment  of  Pulp)  to 
this  problem  of  draining  rag  half-stuff.  If  this  could  be  accom- 
plished, many  advantages  would  be  gained.  The  half-stuff 
could  be  taken  from  the  machine  in  laps  of  uniform  moisture 
content,  and  the  question  of  weight  on  rag  half-stuff  (a  rather 
dubious  figure  in  most  mills)  could  be  settled.     The  rags  might 


Fig. 15 


be  piled  directly  on  skids,  and  these,  wrapped  if  necessary,  could 
be  put  in  storage,  in  the  same  manner  as  pulp.  The  writer  feels 
that  this  method  would  keep  out  much  of  the  foreign  dirt  that  is 
occasioned  by  handling  the  stock  from  the  drainers  to  the  beaters 
in  stock  cars.  In  addition  to  this,  a  much  more  rigid  inspection 
of  the  product  would  be  possible,  since  many  of  the  troubles 
would  show  up  at  once  on  the  wet  machine  and  not  at  the  end 
of  the  paper  machine. 

Fig.  15  illustrates  a  wet  machine.  The  thin  stock  enters 
the  vat  1,  through  pipe  25;  26  is  a  washout.  The  cylinder  5 
collects  fibers  from  the  stock  as  water  passes  through  the  screen 
surface  of  the  cylinder  and  out  at  3  and  4.     An  endless  woollen 


§1  RAGS  AND  RAG  FIBERS  37 

felt,  pressed  down  by  the  couch  roll  2,  takes  the  layer  of  fiber  from 
the  cylinder,  carries  it  over  the  suction  box  11  and  between  the 
press  rolls  18  and  19;  it  winds  up  on  18,  is  cut  off  when 
the  layer  is  right  thickness,  and  is  folded  into  a  bundle  or  lap  on 
table  21.  Pressure  on  roll  18  is  adjusted  by  two  mechanisms 
15,  16,  17.  The  felt  is  carried  on  rolls  6,  7,  8,  9,  10,  13,  and  14, 
and  is  washed  by  a  shower  and  whipper  12.  A  lap  from  a  72-inch 
machine  will  weigh  about  50  lb.,  and  will  contain  about  30%  to 
35%  of  fiber. 

The  practical  questions  are  of  course  whether  the  long  rag 
half-stuff  could  be  handled  by  a  wet  machine  satisfactorily, 
and  whether  the  full  bleaching  effect  of  the  chlorine  would  be 
obtained  in  the  shorter  time  of  contact. 


LOSSES  IN  THE  PROCESS 

60.  Total  Losses. — In  each  step  in  the  preparation  of  rag 
fibers,  there  is  an  attendant  loss  in  weight.  Roughly  the  weight 
of  half-stuff  will  run  from  65%  to  80%  of  the  weight  of  raw 
material  purchased,  depending  of  course  on  the  grade  of  rags  in 
question  and  the  care  used  in  the  processes  of  treatment.  There 
is  also  a  considerable  loss  in  weight  in  storing  rags.  Rags  in 
storage  for  several  months  will  lose  up  to  4%  in  weight.  This  is 
almost  entirely  a  moisture  loss,  and  it  is  probably  fully  regained 
in  the  processing. 

61.  Losses  in  Detail. — The  first  actual  loss  comes  in  the 
removing  of  the  tare  (wrapping).  Under  trade  customs,  this  is 
limited  to  3%,  and,  usually,  it  will  not  average  quite  as  high  as 
this.  Any  tare  in  excess  of  3%  is  chargeable  to  the  dealer  from 
whom  the  rags  were  purchased. 

62.  There  is  some  loss  in  the  rag  thrasher.  In  the  case  of  new 
cuttings,  this  would  probably  be  very  slight — not  over  5%. 
On  street  or  dump  rags,  however,  losses  here  amounting  to  as 
high  as  10%  or  more  are  not  unusual.  In  the  case  of  cleanly 
packed  Thirds  and  Blues,  the  loss  here  will  usually  be  close  to 
2%.  The  dust  from  the  thrashers  consists  of  dirt,  buttons,  etc., 
with  considerable  fiber  dust,  which  is  thrashed  out.  Such  dust 
is  salable  to  roofing  mills  and  to  mills  making  some  of  the  lower 
grades  of  coarse  papers;  it  is  usually  called  a  No.  2  dust. 


38     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

63.  The  next  loss  to  be  considered  is  the  sorting  loss.  This, 
too,  depends  very  largely  on  the  grade  of  rags  being  sorted. 
New  cuttings  may  run  as  low  as  1  %  or  2  % ;  while  in  the  case  of 
old  rags,  this  loss  will  run  from  5%  up,  depending  on  the  quality 
of  the  rags.  In  the  case  of  thirds  and  blues,  from  5%  to  6%  is 
about  the  loss  to  be  expected  where  the  best  rag  obtainable  is 
used.  The  out-throws  are  largely  what  is  known  as  jnuss. 
This  consists  of  stoppings,  seams,  etc.,  in  short,  such  material 
as  must  be  thrown  out  of  the  rags  being  sorted;  it  contains 
metal  and  rubber  in  abundance.  Material  that  is  sorted  out 
because  of  its  color  goes  into  what  is  known  as  blacks,  and  this 
consists  of  hard  or  fast  colors  (as  red  and  yellow)  and  blacks. 
As  in  the  case  of  the  dust,  this  material  is  readily  salable  to  lower 
grade  mills,  and  is  used  in  the  manufacture  of  certain  of  the 
cheaper  grades  of  coarse  papers  and  roofing  papers. 

64.  There  is  a  further  loss  at  the  rag  cutter,  which  is  practically 
constant,  regardless  of  the  grade  of  rags  being  cut;  it  is  due  to  the 
dust  formed  by  the  cutter  knives,  which  is  separated  from  the 
rags  by  the  dusters  at  that  point.  The  loss  in  dust  at  this  point 
will  run  from  1  %  to  l^i%,  depending  somewhat  on  the  equipment 
used.  This  form  of  dust  is  called  No.  1  dust;  it  is  much  superior 
to  No.  2  dust,  being  fairly  clean  and  consisting  largely  of  short 
fibers. 

65.  In  determining  the  losses  due  to  cooking,  washing,  and 
bleaching,  these  three  processes  are  usually  linked  together, 
because  of  the  difficulty  of  arriving  at  the  weight  and  consequent 
losses  at  any  intermediate  step.  Moreover,  these  yields  are 
always  rather  difficult  to  determine  accurately,  even  though  one 
considers  the  three  processes  together;  for  the  rag  that  is  once 
wet  in  the  bleach  boiler  is  not  dried  out  again  until  it  gets  into 
paper.     At  their  best,  then,  these  figures  are  not  any  too  accurate. 

66.  In  the  case  of  new  cuttings,  a  yield  of  85%,  based  on  the 
weight  of  the  dressed  rags,  is  a  figure  that  is  fairly  accurate. 
This  figure  would  of  course  be  too  high  in  cases  where  the  rags 
were  heavily  loaded  with  starch  or  other  material. 

In  the  case  of  such  rags  as  thirds  and  blues,  a  yield  of  75%  to 
80%,  based  on  the  dressed  weight  of  the  rags,  is  about  what 
should  be  expected.  For  street  whites,  however,  this  yield 
would  be  considerably  lower,  and  would  be  nearer  60%  than 
75%. 


§1  FIBERS  OTHER  THAN  RAGS  39 

Many  things  may  come  into  individual  lots  or  types  of  rags 
that  would  change  these  yields  entirely.  For  the  general  run 
of  rags,  however,  they  should  prove  out  fairly  accurate. 


QUESTIONS 

(1)  (a)  What  bleaching  agent  is  generally  used  for  rags?     (6)  how  does 
it  act? 

(2)  How  can  an  excess  of  bleach  be  gotten  rid  of? 

(3)  As  regards  purpose  and  manipulation,   compare  the  drainer  with 
the  wet  machine. 


FIBERS  OTHER  THAN  RAGS 


HEMP,  JUTE,  SEED-HULL  FIBER,  ETC. 


HEMP 


67.  Use  and  Importance. — By  far  the  most  important  of  the 
hemp  fibers  used  for  paper  making  is  the  inanila  hemp.  This 
fiber  is  used  very  largely  by  a  group  of  mills  known  as  makers  of 
rope  papers. 

The  largest  tonnage  of  these  papers  goes  into  sacks,  the  first  in 
importance  being  flour  sacks,  but  also  including  sacks  for  sundry 
uses,  such  as  cement,  lime,  plaster,  etc.  The  manila-rope  fiber 
is  used  on  account  of  its  great  fiber  strength;  also,  for  the  pliability 
of  the  product  which  it  produces. 

Manila-rope  papers  used  for  cable  insulation  purposes  probably 
rank  next  in  importance.  The  copper  conductors  in  power 
cables  are  insulated  by  a  number  of  wraps  of  rope  paper,  slit 
in  widths  from  |  inch  to  2  inches,  after  which,  the  whole  cable  is 
saturated  with  insulating  oil  compounds.  In  telephone  cables, 
the  fine  conductors  are  insulated  with  a  single  thickness  of  very 
thin  manila  paper,  which  is  left  dry  in  the  final  cable.  Other 
uses  of  manila  paper  are  for  sand  paper,  shipping  tags,  gaskets, 
pattern  paper,  and  the  like. 

Note. — Hemp  (Cannabis  sativa).  The  fiber  is  prepared  by  retting,  from 
filaments  that  run  the  entire  length  of  the  stem.  The  ultimate  fibers 
composing  these  filaments  vary  from  5  to  55  mm.  in  length,  averaging  22  mm. 
in  length  and  0.022  in  diameter.     The  ratio  of  length  to  diameter  is,  there- 


40     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

fore,  about  1000:1.  The  fibers  have  very  thick  walls,  which  are  not  very 
highly  lignified.  The  ends  are  large  and  sometimes  flattened,  and  the  central 
canal  is  almost  obliterated.  In  microscopic  appearance,  the  fibers  are  very 
similar  to  those  of  flax;  but  they  differ  from  linen  in  having  greater  ability 
to  break  down  into  fibrilke  (fibrils)  during  the  mechanical  process  of  paper 
making.  Miiller  gives  the  cellulose  content  of  a  sample  of  raw  Italian  hemp 
as  77.13%.  Many  other  plants  yield  fibers  to  which  the  name  hemp  is 
given;  but  they  are  generally  distinguished  as  manila  hemp,  sisal  hemp,  sunn 
hemp,  etc. 

Manila  hemp  (Musa  textilis).  Manila  hemp  is  prepared  from  the  outer 
sheath  of  the  stems  of  the  musa,  which  is  a  species  of  banana.  The  ultimate 
fibers  are  from  3  to  12  mm.  long,  averaging  about  6  mm.  The  width  varies 
from  0.016  to  0.032  mm.,  averaging  0.024  mm.,  the  ratio  of  length  to  width 
being  about  250:1.  The  fibers  taper  very  gradually  toward  the  ends;  the 
central  canal  is  large  and  very  prominent,  while  fine  cross  markings  are 
numerous.  The  percentage  of  cellulose  in  raw  manila  is  given  by  Miiller 
as  64.07  %. 

Agave.  Among  the  most  common  of  the  fibers  of  this  class  is  sisal  hemp, 
or  heniquen,  which  is  largely  employed  for  cordage,  bags,  etc.,  in  which  forms 
it  reaches  the  paper  mill.  The  ultimate  fibers  are  longer  than  manila  fibers, 
rather  smaller  in  diameter,  tapering  and  pointed  at  the  ends,  and  compara- 
tively stiff.  The  central  canal  is  not  prominent,  but  can  be  seen  as  a  narrow 
line  in  some  of  the  fibers.  The  walls  are  thick;  they  are  characterized  by 
many  fine  cross  lines,  close  together,  which  are  found  on  nearly  every 
specimen. 

68.  Source  of  Supply. — The  manila  fiber  used  in  these  papers 
is  practically  confined  to  old  manila  rope.  The  old  rope  is 
collected  by  junk  dealers,  usually  sold  by  them  to  larger  dealers, 
who,  in  turn,  sell  it  to  the  rope-paper  mills.  Such  old  rope  is 
usually  collected  at  definite  places;  such  as  sea  ports,  important 
lake  or  inland  shipping  points,  gas-  and  oil-well  districts,  etc. 
A  very  considerable  amount  of  old  rope  for  paper  making  pur- 
poses is  imported  into  this  country  from  European  points.  The 
manila  fiber  for  rope  making  comes  from  the  Philippines,  and  it 
represents  one  of  the  principal  products  of  these  Islands. 

69.  Preliminary  Treatment. — The  rope  is  inspected,  first,  on 
being  unloaded  and,  again,  and  more  intimately,  at  the  rope 
cutters,  where  any  foreign  material  or  fibers  other  than  manila 
are  thrown  out.  The  rope  is  cut  by  what  is  known  in  the  trade 
as  rag  cutters,  but  the  knife  equipment  of  these  is  so  modified  as 
to  produce  longer  pieces.  The  length  of  the  manila  threads  after 
passing  through  the  rope  cutter  ought  to  be  about  2  inches. 
The  cut  rope  then  goes  through  rotary  dusters,  which  open  up 
the  fibers  and  eliminate  much  of  the  loose  dirt. 


§1  FIBERS  OTHER  THAN  RAGS  41 

70.  Cooking. — From  the  dusters,  the  cut  rope  is  then  fed  into 
the  rotary  boiler.  This  is  the  same  type  of  boiler  as  is  in  general 
use  for  cooking  rags,  and  it  holds  approximately  5  tons.  The 
cooking  liquor  is  made  from  lime  and  soda  ash;  and,  as  is  the  case 
with  rags,  the  strength  of  the  liquor,  the  time  of  the  cooking, 
and  the  steam  pressure  vary  with  the  results  to  be  obtained  and 
the  characteristics  of  the  particular  lot  of  rope  at  hand  to  be 
cooked.     Average  conditions  would  be  about  as  follows: 

For  a  5-ton  boiler,  use  1000  pounds  of  lime  and  500  pounds  of  soda  ash; 
cook  at  25  pounds  pressure  for  10  hours. 

This  cooking  process  removes  the  natural  waxes  and  loosens 
up  the  foreign  dirt  and  grease.  It  makes  the  fiber  softer  and 
more  pliable,  and  greatly  improves  its  working  qualities. 

71.  Washing  and  Bleaching. — The  washing  and  bleaching  are 

usually  done  in  the  beater,  that  is,  as  different  parts  of  the  beating 
process,  without  recourse  to  the  half-stuff,  or  ordinary,  method  of 
treatment.  The  rope-paper  mills  generally  use  beaters  of  from 
800  to  1300  pounds  capacity.  Ordinarily,  the  cooked  fiber  is 
furnished  directly  to  the  beater;  and  the  washing  cylinder  is 
lowered  and  the  washing  process  is  carried  out  in  much,  the  same 
manner  as  rags  are  washed  in  the  washing  engine.  When  the 
washing  is  completed,  the  bleach  is  added.  After  bleaching, 
the  washing  cylinder  is  again  lowered,  and  the  excess  of  bleach  is 
washed  out.  From  this  point,  the  ordinary  beating  process  is 
continued.  The  amount  of  bleach  is  quite  low,  as  a  pure  white 
is  not  attainable  and  is  never  attempted.  Moreover,  a  great 
many  of  the  papers  are  entirely  unbleached;  but  if  bleached,  the 
usual  quantity  of  bleaching  powder  consumed  is  from  5%  to 
10%  of  the  weight  of  rope  furnished. 

72.  Yield. — The  yield  of  manila  rope  as  bought,  compared  with 
the  amount  of  paper  made,  will  run  about  50%  to  65%,  depend- 
ing on  the  thoroughness  of  the  cleaning,  cooking,  and  bleaching 
treatments.  It  can  be  readily  seen  that  a  satisfactory  paper  for 
cement  sacks  can  be  produced  with  much  less  cleaning  than  is 
required  for  a  light-weight,  telephone  insulating  paper. 

Mention  should  be  made  here  of  the  use  of  true  hemps,  which 
are  employed  in  Europe  for  certain  special  papers,  such  as 
Bible,  cigarette,  etc.  The  true  hemp  is  prepared  by  methods 
described;  but  in  the  beater,  it  acts  like  linen,  the  fiber  splitting 


42     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

longitudinally  into  fibrils  which  can  be  felted  into  a  sheet  possessing 
exceptional  formation,  strength,  opacity,  and  finish.  This  fiber 
bleaches  to  a  much  better  color  than  manila  hemp. 


JUTE 


73.  Use  and  Importance. — The  jute  fiber  is  the  isolated  bast  of 
the  jute  plant,  which  is  an  annual  of  very  rapid  growth,  attaining 
a  height  of  8  to  10  feet  in  the  hot  Indian  climate.  To  obtain  the 
bast  fiber,  the  plants  are  cut  down  and  steeped  or  retted  in  a  pool 
of  stagnant  water.  By  this  means,  a  fermentation  process  is 
started.  Wlien  the  retting  is  completed,  the  bast  layer  (which 
is  between  the  bark  and  the  wood)  is  stripped  off  and  washed, 
and  goes  in  this  form  to  the  textile  mill,  where  the  fiber  is  spun 
and  woven  into  twine  or  burlap. 

Jute  fiber  is  extensively  used  in  the  manufacture  of  wrapping 
paper;  it  produces  paper  of  excellent  strength  and  durability, 
being  second  only  to  hemp.  Attention  must  be  called  at  this 
point  to  the  fact  that  jute  is  not  a  pure  cellulose  fiber,  being  what 
is  termed  a  ligno-cellulose,  and  it  is  used  as  such  in  paper  making. 
On  this  account  it  bleaches  to  a  bright  yellow  color,  and  this,  of 
course,  places  certain  limitations  upon  its  use.  The  fiber  is  also 
used  to  some  extent  in  buff  drawing  paper  and  other  papers  of 
that  type. 

74.  Source  of  Supply.— As  is  the  case  with  cotton,  the  raw  fiber 
is  much  too  high  in  price  to  permit  of  its  direct  use  by  the  paper 
maker.  Moreover  jute  cloth  goes  almost  exclusively  into  sacks 
and  other  articles,  which  are  cut  without  waste,  so  that  now 
cuttings  of  jute  are  not  on  the  market.  This  limits  the  supplj'  of 
the  paper  maker  to  old  sacking,  burlap,  and  string,  and  practically 
all  of  the  jute  used  is  from  this  source.  As  is  the  case  with  rags, 
it  is  collected  and  sorted  and  turned  over  to  the  paper  maker  in 
bales. 

The  fiber  from  the  butt  of  the  jute  plant  is  not  suited  to  spin- 
ning; and  a  few  years  ago,  these  jute  butts  were  used  to  a  con- 
siderable extent  by  paper  makers.  Thjs  stock  is  very  dirty  and 
not  particularly  desirable,  and  its  use  is  considerably  restricted. 

Note. — Jute  \Corchorus  cap.mlaris  and  C.  olitorius) .  The  fibers  of  j ute  are 
about  2  mm.  long  and  0.022  mm.  in  diameter.  They  are  thick-walled;  the 
central  canal  is  very  variable,  at  times  being  of  considerable  width  and  then 


§1  FIBERS  OTHER  THAN  RAGS  43 

narrowing  to  luirdlj'  more  than  a  line.  The  surface  is  quite  smooth,  and 
there  may  be  noted  at  intervals  radial  canals  and  joints,  which  are  similar 
to  those  in  linen,  though  not  so  pronounced.  Jute  contains  about  63% 
cellulose  and  24%  ligno-collulose.  As  exported,  the  composition  of  the 
bast  varies,  the  fiber  content  ranging  from  49%  to  59%. 

75.  Preliminary  Treatment. — The  preparation  of  jute  for  paper 
making  varies  considerably  with  the  particular  type  of  paper  that 
is  to  be  made  from  it.  Obviously,  in  the  case  of  a  high-grade 
drawing  paper,  much  more  care  must  be  taken  in  the  sorting, 
washing,  and  bleaching  than  would  be  the  case  when  a  much 
cheaper  product,  such  as  wrapping  paper,  is  to  be  made.  In  the 
former  case,  the  jute  bagging  is  put  through  the  thrasher;  it  is 
then  sorted  over  rapidly  by  women,  who  take  out  the  foreign 
material  that  may  be  present  and  any  pieces  of  rotted  bagging. 
The  stock  is  then  ready  for  the  cutter,  where  it  is  cut,  dusted,  and 
delivered  to  the  boiler  for  cooking.  The  ordinary  type  of  rag 
cutter  and  duster  is  used,  and  the  boiler  is  the  cj-hndrical  rotary, 
in  nearly  all  cases. 

76.  Cooking. — The  reasons  for  cooking  jute  are  similar  in 
man}'  respects  to  the  reasons  for  cooking  rags.  The  cooking 
removes  the  foreign  dirt  and  loading  and  the  natural  waxes  of  the 
fiber,  leaving  it  in  such  condition  that  it  responds  readily  to  sub- 
sequent treatment.  In  cooking  jute,  no  attempt  is  made  to 
cook  out  the  lignin — the  object  is  simpl}-  to  prepare  a  ligno-cellulose 
fiber  for  use  as  such  in  the  paper-making  process.  This  being  the 
case,  it  is  the  practice  to  use  fairl}-  low  temperatures  or  pressures, 
sa}',  20  pounds.  The  cooking  time  most  commonly  used  is  aljout 
10  hours,  although  this  ma}^  be  varied  2  hours  either  way  in  the 
different  mills. 

It  is  the  almost  universal  practice  to  use  lime  as  the  cooking 
chemical.  While  the  quantity  varies  somewhat  with  the  con- 
dition of  the  stock  and  the  result  desired,  the  usual  practice  is 
to  use  from  10%  to  20%  of  lime. 

77.  Washing  and  Bleaching. — In  general,  jute  is  washed  and 
bleached  by  the  same  processes  as  rags.  In  most  cases,  however, 
the  stage  known  as  half -stuff  is  omitted,  the  washing  and  bleaching 
being  done  as  a  part  of  the  beating  process.  That  is,  instead  of 
dropping  the  stock  into  the  drainer  after  it  is  washed  and  bleached, 
the  beating  operation  is  continued  in  the  same  engine,  without 
interrupting  the  process.     In  this  case,  the  stock  is  furnished  into 


44     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

the  engine  after  it  has  been  cooked  and  is  then  throughly  washed 
with  the  washing  cyhnder.  When  the  washing  is  complete,  the 
bleaching  liquor  is  run  in,  and  the  stock  is  allowed  to  bleach  up  to 
the  desired  color.  Dry  bleach  is  often  added  directly  to  the 
engine  when  bleaching  jute.  It  is  usual  to  "sour"  with  a  little 
H2SO4  to  hasten  the  bleaching  action;  but  free  chlorine  may 
form  yellow  lignin  chloride.  The  excess  bleach  is  then  washed 
out  with  the  cylinder  washer;  and  from  this  point,  the  beating 
operation  proper  begins. 

In  bleaching  jute,  about  8%  of  bleaching  powder,  figured  on 
the  dry  weight  of  the  fiber,  is  used,  and  the  stock  comes  up  a 
bright  yellow  color.  Liquid  chlorine  cannot  be  used  successfully, 
as  the  bleaching  solution  must  be  alkaline. 

78.  Yield. — The  yields  from  the  jute  fiber  vary  considerably, 
depending  on  the  care  with  which  the  preparation  of  the  fiber  is 
conducted  and  the  degree  of  washing  and  bleaching.  Since  the 
half -stuff  or  intermediate  form  is  usually  omitted,  it  is  convenient 
to  consider  the  yield  of  paper  from  the  baled  weight  of  the  jute; 
in  the  average  mill,  this  yield  varies  from  50%  to  65%. 


SEED-HULL  FIBER,  BAGASSE,  ETC. 

79.  Cotton-Seed  Hulls. — When  the  cotton  seed  comes  from  the 
cotton  gin,  there  is  left  on  it  a  fuzz  of  short  cotton  fibers,  firmly 
attached  to  the  seed.  This  will  amount  to  approximately  200 
pounds  of  fiber  per  ton  of  seed.  It  has  long  been  the  practice  to 
cut  off  from  60  to  75  pounds  per  ton  of  seed,  as  a  first  cut,  for  use 
in  making  mattresses ;  the  remainder  went  into  the  meal  used  for 
cattle  food.  As  a  development  of  the  war,  it  now  seems  entirely 
possible  that  the  second  cut,  hull  fiber  or  linters,  from  the  cotton 
seed  may  be  made  available  for  use  in  paper  making.  Little  can 
be  said  as  yet  about  this  source  of  raw  material,  as  the  first  mills 
for  its  preparation  in  quantity  are  just  beginning  operation. 
From  figures  now  at  hand,  several  hundred  tons  per  day  may 
become  available,  if  the  experiment  is  a  success.  Just  how,  when, 
and  where  the  paper  maker  will  use  it  remains  to  be  seen,  and 
much  depends  on  what  can  be  done  with  it  after  the  preparation 
problem  is  thoroughly  worked  out.  It  now  seems  likely,  how- 
ever, that  its  place  will  be  as  a  substitute  for  soft  cotton  rags, 
such  as  thirds  and  blues. 


§1  FIBERS  OTHER  THAN  RAGS  45 

80.  Preliminary  Treatment. — A  brief  outline  of  the  present 
ideas  as  to  how  this  material  should  be  handled  follows: 

The  seed  is  first  thoroughly  cleaned  and  all  foreign  dirt  is 
removed;  after  which,  the  first  cut  is  made,  say  of  75  pounds  per 
ton  of  seed.  The  seed  is  then  cut,  and  the  kernels  are  separated 
from  the  hulls.  The  latter  are  treated  in  a  steel  attrition  mill 
for  the  removal  of  the  fiber,  and  the  fiber  and  hull  bran  are 
separated  by  proper  screening. 

81.  Cooking. — The  next  process  is  the  cooking.  The  cooking 
liquor  used  is  caustic  soda,  and  a  fairly  high  concentration  is 
necessary,  say  about  20%  on  the  weight  of  air-dry  fiber.  Experi- 
ments so  far  indicate  that  a  high  pressure  is  needed  (about  80  to 
100  pounds),  and  that  considerable  care  must  be  taken  to  insure 
proper  circulation  of  the  liquor  in  the  boiler.  The  cooking  time 
depends  largely  upon  how  rapidly  the  digester  can  be  brought  up 
to  temperature,  and  it  will  probably  be  found  that  6  to  8  hours 
will  be  the  right  length  of  time. 

Little  can  be  aid  as  yet  with  regard  to  the  type  of  boiler  that 
will  be  used  for  this  work.  To  date,  experiments  have  been 
largely  with  the  soda-pulp  digester.  There  are  two  difficulties  to 
be  overcome  with  the  ordinary  soda  digester,  however;  the 
first  is  that  of  circulation  of  the  cooking  liquor,  and  the  second  is 
the  difiicult}^  of  blowing  the  cook.  Very  few  of  the  cooks  of  this 
material  in  the  usual  soda  digester  will  blow  clean. 

How  the  further  preparation  will  be  carried  out  is  also  rather  a 
question.  The  cooked  fiber  must  be  washed  and  bleached.  It 
will  probably  not  be  possible  to  screen  it  as  a  part  of  its  prepara- 
tion because  of  the  very  nature  of  the  fiber.  This  makes  it  all 
the  more  necessary  that  it  be  thoroughly  cooked,  so  that  the 
bleaching  process  may  destroy  all  the  seed-hull  fragments  that 
are  left  in,  and  which  would  make  dirt  in  the  paper.  Several 
mills  are  said  to  be  using  hull  fiber  and  linters  with  good  results, 
but  details  of  their  methods  are  not  available. 

82.  Use  in  Paper  Making. — The  use  of  this  material  on  any 
extensive  scale  in  the  paper  industry  depends  on  two  factors: 
first,  whether  it  can  be  so  handled  by  the  paper  makers  that  it 
will  produce  the  same  strength,  tear,  and  folding  endurance 
that  are  obtainable  with  soft  rags;  second,  whether  it  can  be 
profitably  produced  in  competition  with  soft  rags  over  a  period 
of  time. 


46     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

83.  Bagasse. — The  crushed  stalks  of  the  sugar  cane,  known  as 
bagasse  or  begass,  have  been  proposed  many  times  as  a  possible 
souice  of  paper-making  raw  material,  and  this  material  has  been 
tried  out  on  several  occasions.  It  is  first  run  through  the  cutter, 
and  is  then  cooked  with  caustic  soda. 

The  pulp  is  easily  reduced,  and  is  readily  washed  and  bleached. 
The  yield  of  pulp  from  the  dry  stalk  is  very  low,  from  20  %  to  30  %. 
This  fact,  together  with  the  fact  that  it  is  generally  rather  dirty, 
and  that  it  ma}^  usually  be  more  economically  used  for  fuel  on 
the  plantation,  has  made  its  use  very  limited.  In  character- 
istics, it  resembles  straw  pulp  rather  closely.  An  interesting  use 
of  bagasse  paper  is  in  covering  young  plants.  The  cane,  or 
pineapple,  pierces  the  paper,  while  weeds  are  smothered,  and 
moisture  conserved. 

84.  Miscellaneous  Fibers. — Almost  any  fibrous  raw  material 
can  be  used  in  the  manufacture  of  paper;  consequently,  there  are 
many  other  fibers,  the  preparation  of  which  might  be  outlined. 
Most  of  these  fibers  are  seldom,  if  ever,  actually  used  in  making 
paper,  however,  and  the  general  method  of  preparation  is  appli- 
cable to  all.  First,  clean  the  fiber  thoroughly;  then  cook  it  with 
an  alkali;  then  wash  and  bleach  it,  and  it  is  ready  to  be  made  into 
paper.  Among  others,  the  following  deserve  mention;  papyrus, 
ramie,  China  grass.  New  Zealand  flax,  saw  grass,  flax  straw  and 
the  paper  mulberry-tree  fiber  of  the  Japanese.  Corn  and  cotton 
stalks  have  also  received  some  attention  in  the  United  States;  there 
is  a  possible  field  of  usefulness  for  them  as  fillers.  Corn  stalk 
fibers  are  very  similar  to  those  of  bagasse. 


ESPARTO 
By  James  Beveridge 


HISTORY  AND  OCCURRENCE 

85.  History. — Esparto  was  introduced  as  a  paper-making 
material  and  as  a  substitute  for  rags  in  1856  by  the  late  Mr. 
Thos.  Routtcop,  a  North  of  England  paper  manufacturer.  Since 
then,  it  has  found  much  favor  in  England  and  in  other  European 
countries,  owing  to  the  quality  of  the  fiber  it  jnelds,  which  is 
specially  suitable   for  the   manufacture   of  high-class   book  or 


§1  FIBERS  OTHER  THAN  RAGS  47 

printing  papers  and  medium-class  writing  papers.  Printing 
papers  made  from  it  are  of  a  soft,  impressionable  nature,  yield- 
ing clear  impressions  from  type  and  blocks.  It  is  largely  due 
to  this  property  that  the  printing  and  book  papers  of  the  highest 
class  in  England  are  so  distinctive  in  character. 

86.  Where  Grown. — The  grass  occurs  in  Spain  and  Northern 
Africa;  it  resembles  in  form  a  stout  wire,  tapering  to  a  fine  point 
at  the  upper  end,  and  varying  in  length  from  12  to  30  inches. 
Owing  to  the  demand,  attempts  have  been  made  to  cultivate 
it;  but  it  grows  wild,  covering  large  areas  in  close  proximity  to 
the  sea  coast,  and  is  somewhat  easily  obtainable.  It  is  pulled 
(not  cut)  and  harvested  by  the  natives,  packed  in  large  pressed 
bales,  and  shipped  in  this  form.  It  differs  in  quality,  according 
to  locality  and  selection,  its  price  being  regulated  accordingly. 
These  qualities  take  the  name  of  the  district  or  Port  from  whence 
they  are  shipped,  such  as  Tripoh,  Sfax,  Oran,  Gabes,  etc.,  in 
Northern  Africa.  The  Spanish  variety,  however,  is  considered 
the  best,  although  now  very  limited  in  quantity,  and  it  commands 
the  highest  price.  This  grass  is  fine,  of  a  bright  russet-yellow 
color,  free  from  the  green  chlorophyl  when  well  matured,  and 
yields  the  highest  percentage  of  fiber.  On  the  other  hand,  the 
varieties  from  Northern  Africa  differ  widely.  Some  are  green, 
coarse,  and  unripe,  yielding  a  lower  percentage  of  fiber,  and  are 
more  difficult  to  reduce  to  pulp  and  to  bleach.  The  additional 
expense  incurred  in  this  treatment  naturally  reacts  on  their 
market  value.  From  whatever  source  obtained,  it  is  recognized 
that  the  fine,  well-matured,  or  ripe  grass  is  more  easily  reduced 
to  fiber  than  the  coarse,  green,  and  unripe  variety;  in  that  it 
requires  less  chemicals  and  yields  more  finished  paper.  Esparto 
should  always  be  kept  under  cover  in  a  dry  place,  as  it  is  apt  to 
heat  and  rot,  if  allowed  to  get  wet. 

Note. — Esparto  (Stipa  tenacissima  and  Lygeum  spartum).  The  bast 
fibers  are  grouped  in  bundles  or  filaments,  which  are  resolved  into  ultimate 
fibers  by  the  chemical  processes  employed.  The  fibers  are  shorter  and  more 
even  than  those  from  straw,  averaging  about  1.5  mm.  in  length,  and  the 
central  canal  is  nearly  closed.  Serrated  cells  are  numerous,  but  are  consider- 
ably smaller  than  those  from  straw,  while  the  smooth,  thin-walled 
cells  are  absent.  The  chief  characteristic  that  distinguishes  esparto  from 
straw  and  other  fibers  is  the  presence  of  small,  tear-shaped  cells  derived  from 
the  hairs  on  the  surface  of  the  leaves.  Cross  and  Bevan  give  the  following 
as  the  percentage  of  cellulose  in  air-dry  esparto:  Spanish,  58.0%;  Tripoli, 
46.3%;  Arzew,  52.0%,;  Oran,  45.6%. 


48     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

87.  Steps  of  the  Process. — The  process  of  reducing  it  to  fiber 
is  a  simple  one,  involving  four  operations,  viz:  (1)  Dusting;  (2) 
boiling;  (3)  washing,  pulping,  and  bleaching;  (4)  screening  and 
making  into  laps.  The  equipment  employed  for  these  operations 
is:  For  (1),  a  willow  or  duster;  for  (2),  an  esparto  boiler,  specially 
constructed  for  the  purpose;  for  (3),  an  ordinary  half-stuff  or 
a  breaking-in  engine  of  the  Hollander  type,  provided  with  a 
drum  washer;  and,  finally,  for  (4),  screening  equipment  and 
presse  pate  machine,  for  running  off  the  bleached  pulp  into  a 
thick  sheet.  In  place  of  the  Hollander,  a  pulping  machine  of 
cylindrical  type  is  sometimes  used;  and,  obviously,  the  fiber  may 
be  screened  before  or  after  bleaching. 


Fig.  16. 


88.  Dusting. — As  the  bales  of  esparto  are  brought  into  the 
mill,  they  are  opened,  and  the  grass  is  loosened  and  fed  into  the 
hopper  A,  Fig.  16,  of  the  conical  duster  or  willow.  A  conical 
screen  revolves  in  a  housing  B,  the  sand  and  dust  fall  through, 
and  the  clean  grass  is  discharged  at  the  spout  C  onto  a  conveyor, 
which  takes  it  to  the  loft  over  the  esparto  boilers.  The  paddle 
D  keeps  the  spout  clear.  In  the  early  days  it  was  deemed  neces- 
sary to  remove  all  roots  by  hand  picking,  girls  being  stationed 
alongside  the  belt  conveyor  for  this  purpose ;  but  as  care  is  now 
taken  to  avoid  pulling  the  roots  while  harvesting  the  grass,  this 
precaution  is  considered  unnecessary.  The  root  ends  of  the 
grass  are  hard,  and  those  that  remain  partly  untouched  by  the 
caustic  liquor  during  the  cooking  are  removed  by  the  screens. 
The  loss  in  weight  during  the  dusting  varies  from  1  %  to  6  % ;  and 
the  grass,  after  dusting,  contains  from  2%  to  3.5%  of  mineral 
matter,  the  bulk  of  which  consists  of  silica,  which  is  soluble  in 
sodium  hydrate,  and  comes  away  in  the  black  liquor  as  silicate 
of  soda. 


§1 


FIBERS  OTHER  THAN  RAGS 
COOKING 


49 


89.  Types  of  Digesters. — A  form  of  digester  in  wliich  the 
boiling  takes  place  is  shown  in  Fig.  17.  It  consists  of  an  upright 
cylinder  M  with  domed  top,  and  fitted  internally  with  a  per- 
forated false  bottom  B,  from  the  center  of  which,  a  vomit  pipe  C 
receives  the  hqiior  that  drains  through  and  carries  it  upward,  to 
pass  again  through  the  body  of  the  grass.     A  steam  jet  I  in  the 


Fig.  1 


bottom  of  this  vomit  pipe,  pointing  upward,  throws  the  caustic 
liquor  against  a  dash  plate  D  at  the  top,  which  distributes  the 
Ij^e  over  the  surface  of  the  grass.  The  boiler  is  also  provided  on 
its  side  with  a  circular  door  H  immediatel}^  above  the  false 
bottom,  to  enable  the  workman  to  remove  the  cooked  fiber,  and 
with  another  door  E,  on  the  top  crown,  for  the  introduction  of 
the  grass.  K  is  a  safety  valve,  and  F  is  a  fitting  for  introducing 
cooking  Hquor  and  wash  water,  if  desired.  Liquor  maj-  also 
be  run  in  through  the  charging  hole. 


50     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 


90.  A  digester  of  a  newer  type,  shown  in  Fig.  18,  resembles  the 
foregoing  in  its  action.  Two  internal  circulating,  or  vomit,  pipes 
A  are  provided,  one  on  each  side  of  the  vessel;  these  throw  the 

liquor  into  the  upper  chambers 
B  under  the  crown,  and  the 
liquor  is  then  distributed  over 
the  surface  of  the  grass,  as 
shown  in  the  illustration. 
Letters  correspond  to  parts 
described  for  Fig.  17.  Ob- 
viously, in  place  of  the  vomit 
pipes,  a  centrifugal  pump  may 
be  used  for  circulating  the 
liquor;  and  the  boiler  and  its 
contents  maj^  be  heated  with 
a  coil,  instead  of  bj^  injecting 
steam  directly  into  the  charge, 
in  a  manner  similar  to  that 
sometimes  employed  in  cook- 
ing wood  pulp.  These  esparto 
boilers  are  built  to  hold  from 
2|  to  3  tons  of  grass  per  charge. 
91.  Cooking  Liquor. — The 
stem  of  esparto  (and  of  grasses 
in  general)  is  largely  cuto- 
cellulose  or  pecto-cellulose, 
instead  of  ligno-cellulose  as  in 
jute.  This  must  be  broken 
up  by  hydrol3^sis,  and  the  non- 
cellulose  substances,  fats  and 
waxes,  rendered  soluble. 
Some  are  changed  to  acids, 
which  unite  with  the  soda; 
others  form  sugars  and  other 
soluble  substances. 

The  resolving  fluid  used  is 
caustic  soda  (sodium  hydrate), 
although  the  so-called  sulphate  processes,  in  which  a  mixture  of 
sodium  hydrate  and  sodium  sulphide  is  used,  is  equallj'  appli- 
cable. The  caustic  liquor  is  obtained  by  causticizing  58%  soda 
ash  with  lime  in  the  usual  way  (see  the  Section  on  Soda  Pulp, 


Fig.  is. 


§1  FIBERS  OTHER  THAN  RAGS  51 

Vol.  Ill),  and  the  amount  of  alkali  used  varies  with  the  quality 
and  kind  of  grass  and  the  treatment.  For  the  finest  quality  of 
esparto,  from  18  to  19  pounds  of  58%  alkali  per  100  pounds  of 
grass  are  enough ;  but  for  the  coarsest  immature  kinds,  as  much 
as  25  pounds  are  required.  These  quantities  of  alkali,  however, 
depend  to  a  certain  extent  on  the  steam  pressure  (or  temperature) 
and  the  time  adopted  for  cooking.  When  high  temperatures 
(or  pressures)  are  used,  less  alkali  is  needed.  The  volume  of 
lye  used  varies  within  somewhat  narrow  limits,  and  would 
depend  on  the  quality  of  the  steam  and  whether  or  not  the  charge 
is  heated  directly,  with  injected  steam,  or  indirectly  by  means 
of  a  heating  coil.  As  a  general  rule,  it  approximates  to  95 
cubic  feet  per  2000  pounds  of  grass  in  the  former  case;  and,  in 
the  case  of  Spanish  esparto,  using  18  pounds  of  alkali  per  100 
pounds  of  grass,  it  would  correspond  to  a  liquor  having  a  specific 
gravity  of  1.048,  at  62°F.  (9.6°  Twaddell),  and  would  contain 
total  alkali  equivalent  to  60  grams  of  soda  per  liter,  of  which 
92%  to  94%  exists  as  hydrate,  the  other  8%  to  6%  being  car- 
bonate. When  25  pounds  of  58%  alkali  are  used,  the  liquor 
would  have  a  specific  gravity  of  approximately  1.066,  at  62°F. 
(13.2°  Tw.) ;  it  would  contain  soda  equivalent  to  84  grams  per  liter, 
of  which  from  92%  to  94%  exists  as  hydrate.  The  time  required 
for  cooking  also  varies,  and  depends  on  the  amount  of  soda  and 
the  steam  pressure  or  temperature;  from  50  to  60  pounds  pres- 
sure is  common  in  modern  esparto  mills.  At  this  pressure  the 
average  cooking  time  occupies  from  2  to  3  hours. 

92.  Cooking  Operation. — The  following  is  a  representative 
example  of  a  cook  in  actual  practice,  in  which  fine,  well  matured 
esparto  was  treated,  the  amount  of  alkali  required  being  18 
pounds  (58%  alkali)  per  100  pounds  of  grass. 

Esparto  (Oran,  fine  ripe  grass) 6000 . 0  lb. 

Caustic  liquor,  volume 285 . 0  cu.  ft. 

Caustic  liquor,  Sp.  Gr.  (10°Tw.) 1 .  050 

Caustic  liquor,  grams  58  %  alkali 60 . 0  per  liter 

Caustic  liquor,  grams  soda  (Na20) 34 . 8  per  liter 

Caustic  liquor,  per  cent  causticization 92 . 0  per  cent 

Time  of  boiling 2§  hours 

Temperature 298°F. 

Pressure  (gauge) 50  lb. 

93.  To  carry  out  this  cooking  operation  in  practice,  the  boiler 
is  first  of  all  filled  with  the  loose  grass,  care  being  taken  to 


52     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

distribute  it  uniformly  inside.  The  liquor  is  then  run  in,  and 
the  vomiting  is  begun.  The  caustic  lye  soon  softens  the  esparto, 
causing  it  to  fall  and  to  pack  somewhat  closely  on  the  perforated 
false  bottom.  As  this  takes  place,  more  grass  is  added  until  the 
whole  charge  of  6000  pounds  has  been  introduced.  The  main 
lid  is  then  securely  bolted  down  and  the  heating  (and  vomiting) 
is  continued  until  the  pressure  reaches  50  pounds.  During  the 
heating;  a  little  steam  is  allowed  to  escape,  by  means  of  a  small 
valve  provided  for  the  purpose,  to  carry  away  the  air  and  light 
oils  inside.  The  pressure  is  maintained  for  2|  or  2|  hours,  after 
which  it  is  blown  down,  the  escaping  steam  being  used  for  heating 
the  next  charge  of  caustic  liquor,  and,  also  the  weak  liquor  for 
the  first  and  second  washings.  When  the  pressure  is  nil,  the 
black  liquor  is  drained  off,  the  hot  washings  from  a  previous 
operation  are  pumped  in,  and  the  vomiting  is  again  begun.  This 
strong  wash  liquor  is  run  direct  to  the  soda-recovery  house  and  is 
mixed  with  the  strong  black  lye.  The  recover}^  of  the  alkali  in 
black  liquors  is  fully  treated  in  Vol.  Ill,  Sections  5  and  6.  Hot 
water  is  now  added,  and  the  grass  is  washed  a  second  time,  the 
weak  liquor  from  this  washing  being  run  off  into  a  tank,  to  be 
used  again  as  a  first  washing  for  the  cook.  The  top  manhole  lid 
is  now  removed,  and,  if  necessary,  further  wash  water  is  added; 
but,  as  this  will  contain  but  a  small  quantity  of  soda,  it  may  be 
run  to  waste.  After  draining  thoroughly,  the  side  door  is 
opened,  and  the  boiled  grass  is  removed  by  hand  into  galvanized 
iron  or  wooden  box  trucks,  or  is  otherwise  conveyed,  to  the 
Hollander  or  bleaching  engine.  When  properly  boiled,  the 
strands  of  grass  will  easily  come  apart,  or  will  be  broken  up  into 
pulp;  in  appearance,  the  original  color  of  the  grass  will  be 
preserved,  but  will  be  brightened. 


WASHING  AND  BLEACHING 

94.  Operation. — Final  washing  and  bleaching  are  usually 
carried  out  in  one  operation,  in  a  Hollander  of  large  capacity, 
fitted  with  drum  washers,  in  order  to  remove  the  last  traces  of 
soda  and  some  intercellular  matter,  which  invariably  passes 
away  with  the  wash  water.  The  bleach  liquor,  consisting  of  a 
solution  of  calcium  hypochlorite  Ca(0Cl)2,  of  a  Sp.  Gr.  of  1.040 
(or  8°Tw.)  is  then  run  in.  In  most  cases  the  temperature  is 
also  raised  to  about  100°F.,  either  by  washing  with  hot  water  or 


§1 


FIBERS  OTHER  THAN  RAGS 


53 


by  direct  heating  with  injected  steam  prior  to  bleaching.     In  this 

way,  the  bleaching  is  hastened.     The  fiber,  after  the  addition 

of  the  bleach  liquor,  quickly  changes  color,  if 

well-matured  grass  is  being  treated;  but  the 

color  changes  more  slowly  if  the  grass  is  green, 

always    assuming    that    no    great   excess   of 

bleach  has  been  added.     The  pulp  is  kept  in 

circulation  for  some  hours;  it  is  then  dumped 

into  a  pulp  chest,  whence  it  is  pumped  to  the 

screens  A,  which  are  usually  placed  at  the 

end  of  the  presse-pate  machine,  Fig.  19.     The 

screened    stock   passes   to    the   flow  box  B, 

which  delivers  it  in  a  quiet,  shallow  stream, 

over  the  apron  C  to  the  Fourdrinier  wire  D. 

Rubber  deckle  straps  E  prevent  escape  over 

the  edges.     Water  drains  through  the  wire, 

some  is  extracted  by  the  suction  boxes  F,  and 

some  by  the   couch  press    (rolls)  G  and  H. 

The  sheet  then  passes  to  the  felt  K,  which 

carries  it  through  the  press  rolls  L  and  M  and 

delivers  it  at  iV,  to  carts  or  a  conveyor.     The 

fiber  is  run  off  on  this  machine  as  a  thick  web, 

and  it  is  taken  to  storage  or  to  the  beating 

engines    for    conversion    into    paper.     As   a 

general    rule,    the    fiber    is   bleached   before 

screening,    as   this   is    considered    a   simpler 

method     than     that     of     screening     before 

bleaching. 

Consideration  should  here  be  given  also  to 
the  wet  machine,  see  Art.  59. 

95.  Yield  Depends  on  Quality. — The  yield 
of  air-dr}'  fiber  containing  10%  moisture, 
from  100  parts  of  grass,  depends  very  largely 
upon  the  quality  of  the  esparto.  From  well- 
matured  Spanish  and  Oran,  it  does  not  exceed 
45%,  while  in  the  case  of  the  unripe  or  green 
kind  it  may  be  as  low  as  40  %  or  even  under. 
Not  more  than  42%  maj^  be  expected,  on  an  I 
average,  from  deliveries  of  North  African  grass. 

96.  The     Sulphate    Process. — Esparto    fiber    may    also    be 
prepared  b}^  the  sulphate  process,  with  equally  good  results. 


^- 


N 


54     PREPARATION  OF  RAG  AND  OTHER  FIBERS 


The  manufacturing  conditions  being  very  similar  to  the  fore- 
going, as  outlined  for  caustic  soda.  For  details  see  Section  6, 
Vol.  Ill,  Manufacture  of  Sulphate  Pulp.  The  advantages  claimed 
for  the  sulphate  method  are :  (1)  A  greater  yield  of  bleached  fiber; 
(2)  a  greater  preservation  of  its  strength.  The  treatment  as  a 
whole  is  also  cheaper,  salt  cake  being  used  in  place  of  soda  ash. 


STRAW  PULP 

97.  Kinds  of  Straw  Pulp. — There  are  two  kinds  of  straw  pulp 
manufactured,  viz.:  (1)  Yellow  pulp,  used  for  the  production  of 
cheap  wrapping  papers  and  straw  board;  (2)  straw  cellulose, 
invariably  put  on  the  market  in  the  bleached  state,  which  is  used 
for  making  the  finest  writing  papers. 

Note. — Straw.  In  straw  pulp,  the  bast  cells  or  fibers  form  the  greater 
part  of  the  pulp.  These  are  comparatively  short  and  slender,  with  sharp 
pointed  ends;  at  quite  regular  intervals  the  walls  appear  to  be  thickened  and 
drawn  together  to  resemble  joints.  The  dimensions  of  straw  fibers  vary  with 
the  kind  of  straw  and  with  the  conditions  of  growth,  nature  of  soil,  etc. 
They  are  longer  than  those  from  esparto,  but  not  so  long  as  the  fibers  from 
spruce  wood,  and  would  compare  more  nearly  with  poplar  fiber  in  paper- 
making  value.  Accompanying  the  bast  fibers  in  straw  pulp  are  numerous 
epidermal  cells  from  the  pithy  portion  of  the  stem.  (See  Fig.  1,  Section  1, 
Vol.  III.)  The  latter  vary  in  shape  from  nearly  round  to  long,  oval  cells, 
whose  length  is  several  times  their  width.  Both  types  of  cell  aid  materially 
in  the  identification  of  straw  pulp. 

Straw  as  used  in  paper  making  includes  the  stems  and  leaves  of  the  various 
cereals.  The  composition  of  straws,  particularly  with  regard  to  the  amount 
of  ash  and  its  constituents,  varies  greatly  with  the  soil  upon  which  they  were 
grown.     Wolff  gives  the  following  analyses  for  different  straws: 


Com, 

% 


Winter 

Winter 

Summer 

Winter 

Oats, 

% 

rye, 

wheat. 

barley. 

barley, 

% 

% 

% 

% 

Water 

Ash 

Fat  and  wax 

Nitrogenous  matter. .  .  . 
Starch,  sugar,  gums,  etc 
Cellulose 


14.3 

14.2 

14.3 

14.3 

14.3 

3.2 

5.5 

7.0 

5.5 

5.5 

1.3 

1.5 

1.4 

1.4 

1.4 

1.5 

2.0 

3.0 

2.0 

2.5 

25.7 

28.7 

31.3 

28.4 

36.2  1 

54.0 

48.0 

43.0 

48.4 

40.0 

14.0 
4.0 
1.1 

3.0 
37.9 
40.0 


See  also  Lloyd,  "The  Structure  of  Cereal  Straws,"  Pulp  and  Paper 
Magazine  of  Canada,  Vol.  xix,  pages  953-4,  973-6,  1002-4,  1025-6,  1048-50, 
1071-5  (1921). 


§1  FIBERS  OTHER  THAN  RAGS  55 

98.  Yellow  Straw  Pulp. — Yellow  straw  pulp  is  manufactured 
by  boiling  the  straw  under  pressure  in  milk  of  lime,  to  which  a 
small  quantity  of  soda  may  be  added;  and,  afterwards,  passing  it 
through  kollergangs  and  beaters,  before  finally  converting  it  into 
paper  or  board.  The  straw  is  cut  into  chaff  of  about  1  to  1^ 
inches  long,  thoroughly  dusted  by  passing  it  through  a  suitable 
willow,  see  Fig.  16,  and  then  digested  in  rotary  boilers,  preferably 
of  the  spherical  type,  Fig.  8,  at  a  pressure  of  40  to  50  pounds 
above  atmosphere,  with  10%  of  its  weight  of  caustic  (quick) 
lime  that  has  been  made  into  a  milk  with  water  and  then  care- 
fully strained,  to  free  it  from  grit.  The  volume  of  liquid  used 
should  be  sufficient  to  cover  the  chaff,  and  the  boiling  should  be 
continued  until  the  particular  kind  of  straw  under  treatment  is 
softened  sufficiently  to  be  broken  up  or  pulped  in  the  disinte- 
grator. When  the  boiling  is  finished,  the  straw  is  washed,  and 
is  then  ground  up  into  pulp  in  the  kollergang  or  beater.  A  yield 
of  100  parts  of  yellow  straw  pulp  requires  133  parts  of  straw, 
(yield  75%),  13.3  parts  of  caustic  lime,  and  20  parts  of  coal  (for 
boiling  only).  The  power  required  to  drive  the  cutters,  digesters, 
kollergangs,  beaters,  and  pumps  is  approximately  25  h.p.  per 
2000  pounds  per  day.  The  product  is  coarse  in  appearance  and 
low  in  strength. 

99.  Straw  Cellulose. — The  routine  of  making  this  product  is 
very  similar  to  that  for  esparto.  The  straw  should  be  as  free 
from  weeds  as  possible,  cut  into  chaff,  then  dusted  (to  get  rid  of 
sand,  etc.)  and,  finally,  boiled  in  a  caustic-soda  solution.  In 
recent  years,  the  sulphate  process  (see  Vol.  Ill,  Section  6)  has 
been  used  with  much  success,  as  it  jdelds  a  cheaper  boiling  fluid, 
a  higher  yield  of  cellulose,  and  a  stronger  fiber,  without  altering 
the  mode  or  routine  of  manufacture  to  any  great  extent. 

100.  Kinds  of  Straws  Used. — The  straws  usually  employed  are 
wheat,  rye,  oat,  and  barley,  though  flax  straw  from  plant  grown 
for  linseed,  being  unsuited  for  textiles,  is  being  developed  as  a 
source  of  paper-making  material.  The  fiber  has  the  character- 
istics of  linen;  but  it  requires  a  drastic  preliminary  treatment, 
as  does  straw.  It  can  be  bleached  to  produce  a  white  paper  of 
good  color  and  strength.  Wheat  and  rye  yield  cellulose  fibers 
that  are  closely  allied  in  point  of  length  and  strength  or  felting  pro- 
perties; oat,  on  the  other  hand,  has  length,  but  is  of  medium  felting 
power;  while  barley  straw  is  short,  soft,  and  of  low  felting  power. 


56     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

All  these  fibers  are  hard  and  crisp  when  bleached  and  dried,  and 
they  impart  this  property  to  the  paper  of  which  they  form  a  part. 

101.  Preliminary  Treatment. — As  a  general  rule,  when  these 
four  varieties  are  available,  a  mixture  of  all  four  is  used.  It  is 
essential  that  they  be  free  from  weeds,  since  it  is  quite  impossible 
to  make  high-grade,  bleached-straw  cellulose  suitable  for  high- 
grade  writings  when  weeds  are  present  to  any  great  extent.  In 
the  best  factories,  the  straw  is  opened  out,  or  is  spread  by  hand 
onto  a  wide  traveling  canvas  belt,  which  leads  to  the  chaff  cutter, 
alongside  of  which,  girls  are  stationed,  whose  duty  is  to  pick  out 
the  weeds.  The  straw  is  then  delivered  to  the  cutter,  which  cuts 
it  into  chaff  from  1  to  1|  inches  long.  From  this,  it  falls  into  the 
willow  or  duster,  and  is  then  blown  through  a  galvanized  iron 
pipe,  into  the  loft  over  the  digesters.  Sometimes  it  is  given 
a  preliminary  dusting  before  it  enters  the  chaff  cutter,  every  care 
being  exercised  to  get  the  chaff  as  clean  as  possible. 

102.  Cooking  Liquor. — The  cut  straw  is  then  digested  in 
rotary  digesters,  either  with  caustic  soda  or  with  a  mixture  of 
hydrate  and  sulphide  of  soda,  as  in  the  sulphate  system  of 
manufacture.  The  following  figures  represent  the  proportion 
of  lye  to  straw  when  cooking  with  caustic  soda  alone,  and,  also, 
other  conditions  of  the  boiling  process,  all  from  actual  practice, 
as  followed  in  a  Dutch  factory : 

Weight  of  straw  (mixture  of  oat  and  wheat)    =  4480  lb.  per  boil 
Amount  of  caustic  lye  =  1610  gal.  (Imperial) 

Time  under  steam  pressure  =         4  hours 

Steam  pressure  (gauge)  =       60  lb.  per  sq.  in. 

Maximum  temperature  =  307°F. 

The  comi)Osition  of  the  above  lye  was  as  follows:  Sp.  Gr. 
1.0525  -  10.5°Tw.;  total  soda  NasO  =  32.49  grams  (=  53.78 
grams  sodium  carbonate)  per  liter,  of  which  about  82  %  existed 
as  hydrate  {i.e.  caustic  soda),  9.3%  as  carbonate,  and  8.3%  as 
silicate,  with  traces  only  of  sulphide.  The  silicate  of  soda  is 
formed  from  the  silica,  which  exists  in  very  appreciable  quantities 
in  all  cereal  straws.  As  the  whole  of  this  silica  is  soluble,  it 
affects  the  consumption  of  the  recovered  soda  liquors  and  the  loss 
of  soda  to  a  very  large  extent,  since  silicate  of  soda  is  quite  useless 
for  the  cooking  operation,  and  must  be  replaced  by  fresh  soda 
ash  in  the  recovery  process. 

103.  Cooking  Process. — The  digesters,  as  previously  stated, 
are  almost  invarial)ly  of  the  rotary  type,  either  horizontal  oi- 


§1  FIBERS  OTHER  THAN  RAGS  57 

vertical  cylinders,  Fig.  7,  or  spheres.  The  latter  revolve  on 
trunnions,  and  are  provided  with  suitable  manholes  and  covers 
for  filling  and  emptying;  also,  with  arrangements  at  the  trunnions 
for  heating  the  digester  and  its  contents  with  steam.  Some- 
times baffle  plates  are  fixed  inside,  to  promote  the  mixing  of  the 
charge;  since  the  straw  softens,  and  is  apt  to  mat  together  into  a 
mass,  which  slips  as  the  digester  rotates.  Several  times  during 
the  boiling,  the  revolving  is  stopped  for  a  few  minutes,  and  the 
air  inside  the  digester  is  allowed  to  escape  through  a  small  relief 
valve.  The  most  suitable  digesters  are  the  spherical  type.  Fig.  8, 
or  the  upright  cylinder  with  coned  ends  (see  Fig.  4,  Section  6, 
Vol.  Ill),  driven  by  worm  gearing,  and  having  a  capacity  of  from 
3  to  4  tons  of  straw.  The  charge  of  pulp  and  black  hquor  may 
be  dumped  or  blown  under  pressure  from  these  digesters  into 
the  wash  tanks  with  greater  care  than  from  those  of  the  horizontal 
cjdindrical  type.  The  digester  space  required  varies  from  120 
to  150  cubic  feet  per  ton  of  bleached-straw  cellulose  made  per 
week.  That  is  to  say,  50  tons  of  fiber  per  week  would  require, 
on  an  average,  about  6750  cubic  feet  of  digester  capacity. 

104.  "Washing  and  Bleaching. — The  contents  of  the  digester 
are  emptied  or  blown  into  the  washing  tanks,  where  the  fiber  is 
washed  by  displacement.  These  tanks  can  be  arranged  accord- 
ing to  Shank's  system,  as  applied  to  the  lixiviation  of  ball  soda  in 
the  Le  Blanc  alkali  process,  in  which  the  wash  Hquor  (or  water) 
flows  from  one  to  the  other  by  gravitation  (see  Fig.  19,  Section  5, 
Vol.  III).  Or,  instead  of  this,  the  washings  may  be  pumped  from 
one  to  the  other,  the  weak  washing  Hquor  being  distributed  over 
the  surface  of  the  fiber  in  the  receiving  tank  by  a  rotating  spray 
pipe,  as  in  the  washing  system  arranged  for  soda  pulp.  In  all 
cases,  since  the  fiber  is  fine  and  settles  down  on  the  filtering 
medium  in  a  somewhat  compact  mass,  the  displacement  of  the 
stronger  lye  by  the  weaker  wash  liquors  (or  water)  goes  on 
slowly,  and  reasonable  time  must  be  allowed  for  washing.  For 
the  same  reason,  an  unusual  amount  of  draining  or  filtering 
surface  should  be  provided,  about  35  square  feet  per  ton  of  pulp 
per  day.  The  washing  of  the  fiber  should  be  conducted  with  the 
greatest  care,  to  avoid  undue  dilution  of  the  black  liquors  going 
to  the  recovery  house;  for  this  reason,  it  should  not  be  hurried. 

The  washed  fiber  is  then  forked  onto  a  travefling  belt  that  is 
placed  over  these  tanks,  and  which  conveys  it  to  a  pulp  opener  or 
rafineur,  to  completely  disintegrate  it;  or  it  is  washed  out  with  a 


58     PREPARATION  OF  RAG  AND  OTHER  FIBERS     §1 

hose,  through  a  valve  or  door  into  a  pulp  chest  that  is  fitted  with 
an  agitator,  and  from  there  is  pumped  to  the  opener.  The  object 
of  the  opener  is  simply  to  break  up  the  bundles  of  fibers.  After 
this,  it  passes  to  the  bleaching  engines — Hollander  or  Bellmer  type 
(Vol.  Ill,  Section  9,  Bleaching  of  Pulp),  where  it  is  given  a  final 
washing  by  a  drum  washer,  Fig.  11,  covered  with  fine-wire  gauze 
(60  meshes  to  the  linear  inch),  with  pure,  clean  water  prior  to  the 
addition  of  the  calcium  hypochlorite  or  bleaching  powder.  As 
in  the  case  of  esparto,  the  temperature  is  raised  to  100°F.  and  the 
pulp  is  allowed  to  circulate  until  it  reaches  the  desired  color. 
Finally,  the  fiber  is  run  off  on  a  presse-pate  machine,  Fig.  19, 
into  a  thick  web,  or  is  passed  over  a  Fourdrinier  drjdng  machine. 

These  different  operations  must  be  carried  out  with  care  and 
intelligence,  to  avoid  contamination  with  dirt;  otherwise,  the 
straw  cellulose  will  not  be  suitable  for  the  production  of  the 
highest-class  writing  papers,  etc. 

105.  Yields. — The  amount  of  cellulose  shown  by  chemical 
analysis  of  these  straws,  is  never  obtained  in  actual  manufacturing 
practice,  because  a  part  of  the  fiber  is  lost  during  its  manipulation 
in  the  factory,  and  a  portion  is  dissolved  b}^  the  caustic  liquor. 
The  percentage  found  by  analysis  even  differs  for  the  same  kind 
of  straw  from  different  districts.  The  whole  question  of  yield 
is  therefore  a  complicated  one.  Barley  straw  yields  much  less 
than  oat,  wheat,  or  rye.  But  when  these  thi'ee  are  used  in  about 
equal  proportions,  100  lb.  of  dry  straw  (8%  to  10%  moisture)  will 
produce  from  40  to  41  lb.  of  bleached  air-dr}^  pulp  containing 
10%  moisture.  The  proportion  of  caustic  soda  used  per  unit 
weight  of  straw  in  the  cooking  has  a  great  influence  on  the  yield 
and  the  bleaching  properties  of  the  fiber,  as  exemplified  by  the 
following  table,  compiled  from  actual  practice  by  Roth: 


Situation  of  works 


1000  Kilos  of  straw 
required 


Soda 
ash 


Lime, 


Bleach 


1000 

Kilos 

of  straw 

yielded 

in  fiber 


100  Parts  of  air-dry 
pulp  required 


Soda 
ash 


Lime 


Bleach 


Kilos   Kilos 


South  Germany  ....  225 

Austria 225 

Saxony I  240 

Bohemia 200 


160 
160 
150 
160 


Kilos 

105 

72 

85 

175 


Kilos 
450 
400 
435 
500 


% 
50.0 
56.25 
55.1 
40.0 


% 
35.5 
40.0 
34.4 
32.0 


% 
23.3 
18.0 
19.5 
35.0 


§1  FIBERS  OTHER  THAN  RAGS  59 

A  study  of  this  table  reveals  the  fact  that  the  yield  of  fiber  is 
varied  indirectly  with  the  amount  of  caustic  alkali  used.  That  is 
to  say,  the  greater  the  amount  of  caustic  alkali  used,  the  less  the 
yield  of  fiber.  Also,  that  the  bleaching  powder  required  increases 
with  the  yield.  These  facts,  it  may  be  stated,  are  common  to  all 
fibers  prepared  by  the  soda  method,  and  they  have  been  con- 
firmed by  many  investigators,  after  careful  experiment. 


QUESTIONS 

(1)  (a)  Where  does  manila  fiber  come  from?     (b)  how  is  it  treated? 

(2)  Why  is  jute  limited  to  the  manufacture  of  coarse  papers? 

(3)  Describe  an  esparto  boiler. 

(4)  What  are  the  several  kinds  of  pulp  straw,  and  the  use  of  each? 

(5)  How  is  straw  cooked  for  a  yield  of  75  %? 

106.  Bamboo. — The  enormous  quantity  of  bamboo  in  the 
world,  and  its  very  rapid  growth,  makes  this  peculiar  grass  a 
promising  source  of  paper-making  material.  The  need  for  its 
exploitation  is  in  sight;  years  of  research  by  Raitt  and  others  have 
shown  the  feasibihty  of  preparing  bamboo  pulp  by  the  soda  or  the 
sulphate  process.  Indian  bamboo  contains  50%  to  54% 
cellulose,  and  Philippine  bamboo  contains  slightly  more.  Raitt 
found  the  soda  process  to  yield  41%  to  43%  of  bleached  pulp 
suitable  for  high-grade  papers.  The  sulphate  process  gives 
about  1%  higher  yield,  with  considerably  less  bleach — 15.5% 
to  18%.  The  sulphite  process  is  unsuited,  because  of  the  amount 
of  silica  in  the  plant  and  the  difficulty  in  maintaining  a  strong 
bisulphite  Kquor  in  the  tropics.  See  Indian  Forest  Records, 
Vol.  3,  Part  3. 

Raitt  recommends  that  (1)  only  shoots  be  cut  that  have 
attained  the  full  season's  growth;  (2)  that  the  culms  be  seasoned 
at  least  3  months  before  use;  (3)  that  it  be  crushed;  (4)  that  the 
starchy  matters  be  extracted;  and  (5)  that  the  sulphate  process 
be  used. 

Satisfactory  digestion  of  the  five  species  investigated  was 
found  to  be  possible  with  20%,  to  22%  caustic  (hydrate  and  sul- 
phide), temperature  162°  to  177°C.,  pressure  80  to  120  lb.  per 
sq.  in.,  and  5  to  6  hour's  cooking  time. 

Note. — Bamboo.  Bamboo  fibers  closely  resemble  those  from  the  straws 
in  many  of  their  characteristics.  According  to  Raitt,  the  average  length  of 
the  ultimate  fibers  is  from  2.20  to  2.60  mm.  according  to  the  variety,  and 
diameters  are  from  0.018  to  0.027  mm.  While  not  so  long  as  spruce  fibers, 
they  are  much  longer  than  those  from  any  of  the  deciduous  trees. 


PREPARATION  OF  RAG 
AND  OTHER  FIBERS 


EXAMINATION  QUESTIONS 

(1)  When  and  where  were  rags  first  used  for  making  paper? 

(2)  What  kinds  of  rags  are  used  for  (a)  writing  paper?  (6) 
wrapping  paper?  (c)  roofing  paper? 

(3)  In  purchasing  rags,  what  materials  would  you  limit  or 
exclude? 

(4)  Describe  the  rag  thrasher,  and  tell  what  it  does. 

(5)  Why  and  how  are  rags  sorted? 

(6)  Describe  the  apparatus  and  the  process  of  cutting  rags. 

(7)  What  is  accomplished  in  the  cooking  of  rags? 

(8)  Describe  one  type  of  rag  boiler. 

(9)  Explain  the  fiUing  of  the  boiler  and  the  cooking  and 
emptying. 

(10)  Name  the  variable  factors  in  cooking,  and  state  how  a 
change  in  each  one  affects  the  others. 

(11)  (a)  Explain  what  happens  to  the  rags  while  washing;  (6) 
how  long  does  this  take,  and  how  much  water  is  used? 

(12)  Why  are  rags  bleached? 

(13)  How  is  the  bleach  liquor  prepared  for  bleaching  rags? 

(14)  Express  your  opinion  of  a  foreman  who  used  12%  of 
bleach  for  Thirds  and  Blues  and  added  a  chemical  to  neutrahze 
the  excess. 

(15)  (a)  What  are  the  items  of  loss  in  preparing  rags?  (6)  how 
do  these  vary  with  different  classes  of  rags? 

(16)  What  kinds  of  paper  are  made  from  manila  hemp? 

(17)  How  does  jute  differ  from  other  fibers  considered  in  this 
Section? 

(18)  What  is  the  prospect  of  using  cotton-seed  hull  fiber  or 
linters  in  paper  making? 

(19)  What  is  the  source  of  esparto,  and  for  what  papers  is  it 
used? 

(20)  (a)  How  is  straw   cellulose  prepared?   (6)   what  is  the 

average  ^deld? 

§1  '  «l 


SECTION  2 

TREATMENT  OF  WASTE 
PAPERS 

By  Ed.  T.  A.  Coughlin,  B.  S.,  Ch.  E. 


USE,  VALUE,  RECOVERY  AND  GRADING 

USE  AND  VALUE  OF  WASTE  PAPERS 

1.  Reasons  for  Extensive  Use  of  Waste  Papers. — The  use  of 

printed  waste  paper,  or  old  paper  stock,  as  it  is  commonly  called 
in  the  mill,  has  developed  to  such  an  extent  on  this  continent 
that  it  rivals,  even  surpasses  in  some  cases,  the  use  of  soda  and 
sulphite  pulps  in  certain  grades  of  paper.  There  are  many- 
reasons  why  old  paper  stock  has  reached  this  point  of  importance, 
some  of  which  are:  the  immense  available  supply  of  material; 
the  low  cost  of  material ;  low  cost  of  converting  into  paper  pulp ; 
desirability  of  the  converted  product. 

2.  At  the  present  time,  old  paper  stock  is  employed  in  the 
manufacture  of  container  board,  box  board,  wall  board,  leather 
board,  papier-mache,  roofing  paper,  manilas,  carpet  paper, 
wrapping  paper,  bag  paper  and  printing  papers.  In  the  finer 
grades  of  paper,  such  as  book  and  printing  paper,  bod}^  stock  of 
coated  paper,  lithograph  and  book  papers,  the  cheaper  grades 
of  writing,  mimeograph,  offset,  drawing,  bible,  blotting,  map, 
parchment,  music,  catalog,  tissue,  water  leaf  and  cover  papers, 
the  percentage  of  old  paper  stock  used  in  them  ranges  from  10% 
to  80%  of  the  furnish. 

3.  It  would  be  difficult  to  ascertain  the  limits  of  the  field  for 
consumption  of  old  paper  stock.  This  material,  when  properly 
de-fibered  and  freed  from  colors,  dirt  and  ink,  can  be  safely 
used  in  all  but  the  finest  grades  of  writing  and  record  papers, 
and  in  papers  that  call  for  a  specially  long  fiber,  where  the 
§2  1 


2  TREATMENT  OF  WASTE  PAPERS  §2 

composition  of  the  sheet  to  be  made  has  been  specified  previously. 
Consequently,  it  is  not  strange  that  what  formerly  was  a  waste 
and  a  useless  commodity  now  finds  a  ready  application  to  almost 
every  grade  of  paper  made. 

By  far  the  largest  tonnage  of  this  waste-paper  material  is 
re-made  into  boards,  liners  and  newsprint;  in  fact,  it  has  been 
estimated  that  about  10,000  tons  of  old  paper  stock  is  daily 
re-made  into  the  classes  of  paper  here  mentioned,  and  about  2500 
tons  is  employed  daily  in  the  manufacture  of  book,  writing  and 
the  other  grades  of  the  better  class  previously  referred  to.  This 
Section  will  deal  more  particularly  with  this  latter  application 
of  the  great  American  waste. 

As  a  subject  for  discussion,  "The  Reclamation  of  Printed 
Waste  Paper"  has  been  almost  as  popular  a  theme  as  "A  New 
Substitute  for  Wood  Pulp."  For  years,  it  has  been  the  goal 
of  many  determined  paper  makers,  of  many  enterprising  business 
men,  also  of  many  adventurous  fakers,  to  work  over  old  maga- 
zines, books,  letters  and  bill  heads,  and  even  old  newspapers, 
in  such  a  manner  as  to  produce  a  grade  of  paper  equal  in  every 
respect  to  the  original.  Many  machines  have  been  devised, 
and  many  processes  have  been  worked  out  in  secret,  to  re-pulp 
and  de-ink  discarded  paper,  but  a  large  proportion  has  resulted 
in  economic  failures.  Notwithstanding  quite  extensive  skepti- 
cism concerning  the  practicability  of  the  process,  thousands  of 
tons  of  paper  are  daily  being  re-made  into  high-class  book  and 
printing  papers  and  similar  grades,  which  compete  with,  and 
sometimes  quite  materially  undersell,  the  pure-fiber  papers. 

4.  Value  of  Waste  Paper. — A  more  general  appreciation  of  the 
market  value  of  rags,  rope,  and  waste  paper  of  all  kinds,  would 
increase  largely  the  supply  of  old  paper  stock;  it  would  also  add 
considerably  to  the  income  of  the  general  public.  According  to 
figures  for  1919  by  the  U.  S.  Department  of  Census,  rags  to  the 
value  of  §23,000,000  were  used  in  that  year  for  paper  making, 
besides  $7,000,000  of  rope,  jute  bagging,  waste,  threads,  etc.,  while 
several  times  this  amount  could  be  secured  under  proper  collect- 
ing conditions.  Waste  paper  to  the  value  of  $43,000,000  was 
used  in  1919  in  paper  making,  and  it  is  estimated  that  three 
times  this  amount  could  be  made  available.  Even  though  1919 
was  a  period  of  high  prices,  it  is  therefore  evident  that  the  value 
of  the  waste  paper  annually  destroyed  is  very  great ;  if  reclaimed 
and  used,  it  would  serve  a^double  purpose — the  production  of 


§2  USE,  VALUE,  RECOVERY  AND  GRADING  3 

good  paper,  and  the  conservation  of  the  material,  largely  wood, 
that  the  waste  paper  replaces.  The  1,000,000  tons  of  paper  now 
wasted  each  year,  and  which  could  be  saved,  would  make  all  the 
building,  bagging,  cover,  blotting  and  miscellaneous  papers,  and 
all  the  paper  board,  that  is  now  produced. 

Considering,  then,  the  immensity  of  the  field  and  the  profits 
to  be  derived,  it  is  only  logical  that  many  methods  should  have 
been  devised  and  patented  for  reclaiming  old  paper  stock. 


METHODS  OF  RECOVERY 

5.  Classification  of  Methods. — It  would  be  almost  an  impossi- 
bility to  collect  and  record  all  the  different  methods  that  have 
been  patented.  Those  processes  that  are  in  practical  use  in  the 
mills  will  be  considered  in  detail.  The  methods  are  here  treated 
under  three  heads:  mechanical  action  alone,  without  the  use  of 
chemicals;  chemical  action  alone;  combined  mechanical  and 
chemical  action.  For  each  class,  many  processes,  and  the  equip- 
ment therefor,  have  been  patented.  Some  of  these  show  a  lack 
of  knowledge  or  experience  regarding  their  practical,  economical 
operation.  It  may  be  remarked  that  few  branches  of  the  paper 
industry  have  brought  out  more  patents  than  this. 

6.  Mechanical  Processes. — Very  few  methods  of  any  value  are 
to  be  found  in  the  class  that  includes  the  processes  grouped  under 
mechanical  action  alone;  for,  to  produce  a  good  white  pulp  for 
book  paper,  it  is  necessary  that  the  inks  be  entirely  removed. 
Printing  inks  consist  mainly  of  some  pigment,  which  is  combined 
with  an  oil  or  varnish  body,  called  the  vehicle.  To  remove  the 
ink,  saponification  b}-  an  alkali  of  some  kind  is  necessary,  in 
order  to  effect  a  combination  of  the  alkali  with  the  vehicle  and 
free  the  pigment.  However,  under  mechanical  action  alone 
may  be  classed  all  methods  employed  in  roofing  and  board  mills 
that  use  only  old  newspapers,  wrapping  papers,  and  box  boards. 
For  the  grade  of  paper  there  produced,  the  color  is  of  secondary 
importance,  and  the  products  are  usually  heavily  colored  with 
loading  ochers  and  red  oxides. 

7.  Chemical  Processes. — Treatment  of  papers  by  chemical 
action  alone  is  understood  to  refer  to  those  processes  in  which  the 
papers  remain  stationary,  the  liquor  used  being  allowed  to 
circulate  and  permeate  the  mass  thoroughly.     In  this  way,  the 


4  TREATMENT  OF  WASTE  PAPERS  §2 

ink  is  broken  up,  being  deprived  of  its  vehicle,  and  it  is  easily- 
washed  out  subsequently  in  the  washing  engines.  This  method 
is  the  practical  outcome  of  the  earliest  experiments  in  treating 
waste  papers;  it  is  called  the  open-tank  cooking  process,  and  it  is 
stilljargely  in  vogue  in  mills  of  the  Middle  West. 

8.  The  first  description  of  a  process  of  this  type  is  credited  to 
J.  T.  Ryan,  of  Ohio,  and  was  patented  by  him.  After  being 
dusted,  the  papers  are  cooked  with  a  soda-ash  solution  of  5°Be. 
at  160°r. 

In  the  method  patented  by  Horace  M.  Bell  and  Edmund  R. 
Lape,  of  Swanton,  Vt.,  the  dusted  papers  are  agitated  in  a  solu- 
tion of  1  part  soap  and  600  parts  water  for  each  10  parts  of 
papers;  the  loosened  ink  is  then  washed  away. 

9.  Combined  Mechanical  and  Chemical  Processes. — By  far 

the  greatest  number  of  actual  and  proposed  methods  depend 
on  the  combined  chemical  and  mechanical  treatment  of  the 
papers;  the  most  important  of  these  is  the  rotary-boiler  process, 
the  details  of  which  will  be  thoroughly  discussed  later.  The 
cooking-engine  process,  and  several  other  patented  processes 
will  also  be  considered  in  detail. 

10.  John  M.  Burby  states,  in  U.  S.  patent  No.  1,112,887,  that 
alkalis  are  most  suitable  for  use  as  solvents  in  processes  for  the 
recovery  of  pulp  from  printed  waste  papers;  but,  if  they  are 
used  in  solutions  containing  more  than  the  equivalent  of  2  parts 
of  caustic  soda  to  1000  parts  of  water,  or  if  weaker  solutions  are 
employed  at  a  temperature  of  150°F.  or  higher,  they  produce  a 
discoloring  effect  on  the  mechanical  wood  pulp  that  may  be 
contained  in  such  waste  papers.  Mr.  Burby  found  that  a  solu- 
tion of  1  part  (or  even  less  than  1  part)  of  caustic  soda,  measured 
by  weight,  in  1000  parts  of  water,  if  employed  in  proportionate 
quantities,  is  sufficient  in  most  cases  to  counteract  the  adhesive- 
ness of  the  oily  medium  of  printer's  ink.  Other  alkalis  may  be 
used  in  place  of  caustic  soda. 


CLASSIFICATION  OF  WASTE  PAPERS 

11.  Grades  of  Papers. — Until  recently,  no  definite  standards 
or  distinct  classes  were  deemed  to  be  necessary  in  the  classifica- 
tion of  waste  papers.  Perhaps  the  first  distinctions  made  were : 
(a)  Waste  papers  for  No.  1  stock,  such  as  shavings  and  cuttings 


§2         USE,  VALUE,  RECOVERY  AND  GRADING  5 

of  papers  not  printed  upon  and  which  could  be  used  directly  in 
the  beater  without  preliminary  treatment;  (6)  waste  papers  for 
book  stock,  which  comprises  practically  all  kinds  of  printed 
matter  except  groundwood,  or  mechanical,  pulp  papers;  (c)  all 
other  waste  papers,  which  are  made  into  cheap  box  board. 

12.  Quite  naturally,  paper  manufacturers  using  these  wastes, 
especially  book-paper  men,  noticed  that  certain  grades  of  paper 
produced  a  cleaner  and  more  uniform  sheet,  and  they  therefore 
discriminated  in  their  selection  of  stock;  this  has  resulted  in  the 
following  grades  of  waste  papers,  with  their  prices  per  100  lb.,  the 
latter  fluctuating  according  to  the  season  and  to  the  demand: 

Quotations  on  Waste  Paper  Oct.,  1915  Oct.,  1922 

No.  1  hard  white  shavings $2 .  40  -2 .  50  14 .  20-4 .  40 

No.  2  hard  white  shavings 2 .  00  -2 .  10  3 .  75-4 .  15 

Ledger,  solid  books 1.75-1.85  3.00-3.25 

No.  1  soft  white  shavings 1 .  75  -1 .  80  3 .  75-3 .  90 

Ledger  stock 1.40-1.50  2.70-2.80 

Magazine,  flat 0.80-0.90  2.45-2.50 

Magazine,  unstitched,  flat 0 .  95  -1 .  00  2 .  65-2 .  70 

Crumpled  book  stock 0.70-0.75  2.10-2.15 

White  blank  news 1.05-1.10  2.00-2.15 

New  manila  envelope  cuttings ....  1 .  50  -1 .  60  2 .  50-2 .  60 

Newmanilas 1.30-1.40  2.00-2.10 

Manilas,  extra 0.90-1.00  1.80-1.90 

Manilas,  No.  1 0.65-0.75  1.50-1.60 

Manilas,  No.  2 0.35-0.45  1.40-1.50 

Bogus  wrappers 0.42^-0.45  1.10-1.20 

No.  1  mixed  papers 0.30-0.35  1.05-1.15 

Ordinary  mixed  papers 0.25-0.30  0.80-0.90 

Over-issues 0.50-0.55  1.20-1.25 

Folded  news 0.35-0.40  1.25-1.35 

Box  maker's  cuttings 0 .  30  -0 .  35  1 .  05-1 .  15 

Telephone  books 0.25-0.30  0.55-0.65 

Even  with  these  distinct  grades,  the  mills  are  continually  being 
annoyed  with  shipments  that  do  not  approach  the  quality  speci- 
fied in  the  orders.  If  there  is  to  be  any  profit  at  all,  it  is  practi- 
cally impossible  for  the  original  packers  to  grade  so  closely  that 
the  stock  can  be  used  without  subsequent  mill  sorting,  particu- 
larly in  the  case  of  magazine,  book,  and  mixed  ledger  grades. 
In  these  items,  an  allowance  of  3%  for  groundwood  is  made  to 
the  packers;  all  over  this  amount  is  deducted  from  the  original 
price  of  the  stock,  and  is  paid  for  as  "print. "  In  magazine  stock, 
an  allowance  of  3%  is  made  for  any  book  stock  that  may  be 


6  TREATMENT  OF  WASTE  PAPERS  2§ 

found  on  sorting;  if  a  greater  percentage  is  found,  it  is  paid  for  as 
ordinary  book  stock.  Similar  allowances  are  made  in  mixed 
ledger  stock,  which  is  very  hard  to  grade. 


WASTE-PAPER  STANDARDS  AND  PRICE  FLUCTUATION 

13.  A  Satisfactory  Standard. — For  a  long  time,  there  was 
considerable  difference  of  opinion  as  to  how  to  grade  a  paper  over 
which  there  was  a  controversy  regarding  its  correct  classification. 
No  set  standards  were  in  general  use  among  packers  until  the 
Theodore  Hofeller  Company,  of  Buffalo,  N.  Y.,  issued  a  set  of 
standards,  which  were  found  to  be  satisfactory  to  all  the  trade. 
This  classification  is  as  follows : 

14.  No.  1  Book  and  Magazine  Stock. — No.  1  books  and 
magazines  must  be  free  from  groundwood  paper,  parchment 
paper,  magazine  covers  made  of  dark-colored  paper,  school  paper, 
paper  shavings,  photogravure  paper,  and  free  from  books  with 
burned  edges.  The  following  are  some  of  the  books  and  maga- 
zines that  will  not  be  accepted  as  No.  1  books  and  magazines: 
Ainslee's,  All  Story,  Blue  Book,  The  Cavalier,  Pearson's,  Popular, 
Red  Book,  Top  Notch,  Short  Stories,  catalogues  from  mail  order 
houses,  cheap  novels,  telephone  books,  etc.  Thick  books,  ap- 
proximating the  size  of  Dun's  Agency  books,  should  be  ripped 
apart,  making  each  part  the  thickness  of  an  ordinary  magazine. 

15.  Ledger  Stock.^ — Ledger  stock  consists  of  high-class 
writing  paper,  account  books,  ledgers,  letters,  checks,  bonds, 
insurance  policies,  legal  documents,  etc.  The  paper  may  be 
white  or  tinted,  it  may  be  torn  into  two  or  three  parts,  but  it 
must  not  be  torn  into  small  pieces.  Covers  must  be  removed 
from  books  and  ledgers.  The  following  will  not  be  accepted  as 
ledger  stock:  Postal  cards,  school  papers,  telegrams,  envelopes, 
parchment  paper,  tissue  paper,  copying  books,  manila  paper, 
colored  paper,  railroad  bills  of  lading,  freight  bills,  ledgers  or 
books  with  burned  edges. 

16.  Mixed  Paper  Stock. — Mixed  paper  consists  of  clean,  dry 
paper  from  stores,  offices,  schools,  etc.  It  may  include  wrapping 
paper,  cardboard  boxes,  paper  book  covers,  pamphlets.  No.  2 
book  stock,  telephone  books,  crumpled  newspapers,  envelopes 
and  paper  torn  into  small  pieces  that  is  not  good  enough  for 
book  stock  or  ledger  stock.  The  paper  must  be  free  from  excel- 
sior, sticks  of  wood,  rubbish,  iron,  strings,  rags,  leather  or  cloth 


§2         USE,  VALUE,  RECOVERY  AND  GRADING  7 

book  covers,  free,  in  fact,  from  all  material  that  cannot  be  manu- 
factured into  paper.  Bricks,  concrete,  and  even  dead  cats  have 
been  found  in  waste  papers. 

17.  Newsprint  Stock. — Folded  newspapers  must  be  clean, 
dry,  flat,  folded  newspapers,  such  as  come  from  private  homes, 
newspaper  offices,  news  stands,  libraries,  etc.  Pamphlets, 
mixed  papers,  and  crumpled  newspapers,  will  not  be  accepted 
as  folded  news. 

18.  Subdivisions  of  Standard  Grades. — In  book-paper  mills, 
there  is  a  considerable  variety  in  the  grades  of  paper  made;  as  a 
consequence,  a  difference  in  the  quality  of  old  papers  used  in  the 
furnish  is  called  for.  Most  mills  have  only  two  grades,  which 
they  call  No.  1  and  No.  2.  The  No.  1  grade  is  made  up  chiefly 
from  ledger  stock,  for  solid  ledger  books  form  a  very  fine  sheet. 
The  No.  2  grade  is  made  from  magazines  and  books;  and,  although 
a  good  sheet  can  be  made  from  this  stock,  it  does  not,  of  course, 
command  as  good  a  price  as  that  made  from  No.  1.  These  two 
grades  are  sometimes  further  subdivided  by  calling  the  paper  made 
from  them  Extra  No.  1  or  No.  2,  and  Special  No.  1  or  No.  2.  This 
difference  is  created  by  the  use  of  high-grade  ledgers  and  No.  1 
school  books,  or  by  a  variation  in  the  pulps  used. 

19.  Another  Standard  Classification. — The  following  Standard  Classifica- 
tion for  Waste  Paper  has  been  adopted  by  the  National  Association  of  Waste 
Material  Dealers  to  be  effective  from  July  1,  1922,  to  July  1,  1923.  Any 
person  wishing  to  have  this  circular  mailed  to  them,  should  forward  their 
request  to  the  Secretary,   Times  Building,  New  York. 

Baling.  Unless  otherwise  specified,  it  is  understood  that  all  ^ades  are 
to  be  in  machine  pressed  bales. 

Tare.  It  is  understood  that  unless  otherwise  specified,  tare  shall  not 
exceed  3  %. 

Weights  and  Quantities.  A  carload,  unless  otherwise  designated,  shall 
consist  of  the  weight  governing  the  minimum  carload  weight,  at  the  lowest 
carload  rate  of  freight,  in  the  territory  in  which  the  seller  is  located. 

Hard  White  Envelope  Cuttings.  Shall  consist  of  all  white,  hard-sized 
(writing)  papers,  to  be  free  of  groundwood,  ink  and  all  foreign  substances. 

Hard  White  Shavings.  Shall  consist  of  hard-sized,  white  writing  paper, 
free  from  colors  and  tints,  groundwood,  and  other  substances.  May  contain 
machine-ruled  and  unruled  paper  but  not  print-ruled. 

Soft  White  Shavings.  Shall  consist  of  all  white  book-paper  cuttings, 
free  from  groundwood,  ink,  colors,  and  not  to  contain  over  10%  of  coated 
papers 

No.  1  Heavy  Books  and  Magazines.  Shall  contain  all  books  and 
magazines,  which  are  to  be  free  of  crumpled  and  scrap  papers,  and  shall  not 
contain  to  exceed  3%  of  groundwood,  leather,  cloth  and  board  covers. 


8  TREATMENT  OF  WASTE  PAPERS  §2 

Mixed  Books  and  Magazines.  Shall  consist  of  magazines  and  books, 
to  be  free  from  all  other  kinds  of  paper.  They  must  not  contain  more  than 
20%  groundwood  papers,  leather,  board  and  cloth  covers  and  foreign 
substances. 

Kraft  Papers.     Shall  contain  all  kraft  papers,  free  of  waterproof  papers. 
No.    1   Print   Manilas.     Shall  be  composed  of  a  majority  of  manila 
colored   papers,  writing  papers  and  office  waste.     It  must  be  free  of  soft 
papers,  news  and  box  board  cuttings. 

Container  Manilas.  Shall  consist  of  manila  and  other  strong  papers, 
with  soft  papers  such  as  news  and  box  board  papers  eliminated. 

Newspapers,  Shall  contain  dry,  clean  newspapers,  free  from  all  foreign 
substances  not  suitable  for  the  manufacture  of  paper. 

Mixed  Papers.     Shall  consist  of  all  grades  of  dry  waste  paper,  free  from 
objectionable  material  or  materials  that  cannot  be  manufactured  into  paper. 
Note.     Variations  of  the  above  grades  or  grades  not  included  in  this 
classification  are  to  be  sold  by  description  and  sample  or  by  sample. 

20.  Price  Fluctuation.^ — The  fluctuation  in  the  prices  of  the 
different  grades  of  waste  papers  presents  an  interesting  study; 
it  is  a  direct  indicator  of  conditions  among  the  mills.  For 
instance,  the  price  of  No.  1  magazine  stock  varied  from  $0.60 
to  $0.90  in  1911,  and  from  $0.75  to  $1.10  in  1907;  these  figures 
include  the  highest  and  lowest  prices  in  the  years  1907  to  1912. 
These  figures  are  quoted  for  the  years  given  because  the  prices 
in  the  war  years  do  not  represent  normal  conditions. 

Variation  in  price  is  due  to  the  law  of  supply  and  demand,  and 
is  also  influenced  by  the  seasons.  In  the  spring  and  summer 
months,  the  collections  increase,  and  the  supply  on  hand  with 
the  packers  increases  to  such  an  extent  that  storage  costs  neces- 
sitate a  quick  and  ready  market;  as  a  result,  the  price  naturally 
drops.  In  the  fall  and  winter  months,  the  mills  having  stocked 
up  to  full  capacity,  the  demand  for  paper  stock  lessens;  but,  by 
reason  of  the  increased  cost  of  collecting,  the  prices  usually 
increase.  However,  the  price  of  the  higher  grades  of  ledger  and 
shavings  is  not  so  flexible;  the  price  of  these  is  governed  mainly 
by  the  available  supply,  and  by  the  ruling  price  of  the  rags  or 
bleached  sulphite  that  enters  into  the  manufacture  of  new  paper. 


QUESTIONS 

(1)  Compared  with  the  total  supply  available,  what  is  the    probable 
proportion  of  waste  paper  collected? 

(2)  Under  what  classification  can  the  processes  of  treating  waste  papers 
be  placed? 

(3)  What  is  the  nature  of  printing  ink,  and  what  chemical  action  is  usually 
jiecegsary  to  get  rid  of  it? 


§2 


SORTING,  DUSTING  AND  SHREDDING 


9 


(4)  Name  a  class  of  papers  for  the  manufacture  of  which,  chemical  treat- 
ment of  the  waste  paper  used  is  not  required,  and  state  why. 

(5)  On  what  basis  are  waste  papers  classified  ? 


SORTING,  DUSTING  AND  SHREDDING 


MILL  SORTING 

21.  General  Layout  of  Mill  and  Sorting  Rooms. — The  general 
plan,  or  layout,  of  old-paper  sorting  rooms  is  practically  the 
same  in  all  mills.  The  sorting  rooms  are  usually  situated  in  a 
comparatively  isolated  part  of  the  mill,  to  avoid  getting  dirt 
in  the  finished  paper;  they  are  generally  on  the  top  floor  of  the 
mill,  so  the  papers  can  be  delivered  by  gravity  to  the  cooking 


H 


a 


H 


D 


Approximate  Scale 


TT 


0' 


100 


200 


Bldg. 

Construction 

Purpose 

A 

4  Stories  and  basement 

Paper  storage  and  sorting 

B 

4  Stories  and  basement 

Paper  storage,  cutting  and  dusting 

C 

2  Stories  and  basement 

Cooking  building 

D 

1  Story  and  basement 

Beater  room 

E 

1  Story  and  basement 

Machine  room 

F 

1  Story  and  basement 

Finishing  room 

G 

1  Story  and  basement 

Packing  and  shipping  room 

H 

1  Story  and  basement 

Power  plant 

J 

1  Story  and  basement 

Repair  shop 

Fig.  1. 


or  bleacher  room.  This  arrangement  causes  the  various  steps  to 
be  progressive,  in  the  course  of  manufacture,  and  makes  the 
process  continuous.  A  glance  at  Fig.  1,  which  is  a  plan  of  the 
mill,  will  make  this  clear. 


10 


TREATMENT  OF  WASTE  PAPERS 


§2 


The  sorting  room  must  be  well  lighted  and  ventilated,  since 
light  is  essential  for  close  sorting;  and  the  dust-laden  air  must 
be  continuous!}^  removed,  to  preserve  the  health  of  the  sorters. 
A  diagram  giving  the  general  sequence  of  the  various  operations 
is  shown  in  Fig.  2. 


Wasfe  Paper 
in  Bales 


Soda  AsH  or 
OVher  Alkali 


Unbalinq 
and  Sor+ing 


M 


ixing 


Tank 


CuHing 
and  DusTing 


Cookino|  Liquor 
Siorage  Tank 


X 


Soaking  Tank 
or  Mixing  Engine 


Cook mg  and 
De-  Fibering 


Pm  Cai-chers 
and  Screens 


Washing  and 
Thickening 


B I eaching 
(If  Required) 


Storage  for 
De-Inked  S+ock 


Fir,.  2. 


BENCH  SYSTEM  OF  SORTING 

22..  Description  of  Bench  System. — When  the  waste  papers 
reach  the  mill,  thej'  are  weighed  in  by  the  storehouse  foreman, 
and  the  weight  is  written  on  a  tag,  which  is  securely  fastened  to 
the  bale.  If  there  is  room  for  it,  the  stock  is  placed  on  a  car, 
sent  up  on  an  elevator  to  the  sorting  room,  and  run  alongside 


§2 


SORTING,  DUSTING  AND  SHREDDING 


11 


the  benches,  if  the  sorting  room  is  well  supplied  with  them;  after 
the  car  has  been  unloaded,  the  stock  is  placed  in  the  storehouse, 
in  numbered  bays.  The  storehouse  foreman  of  a  book-paper  mill 
is  well  quahfied  to  judge  the  quality  of  the  stock  as  it  comes  to 
him;  and  if  he  thinks  it  will  run  excessively  to  print  or  discards, 


UP 

a     o 

I] 

u 
I] 
u 

3 
U 

I] 


uuuuuu 


E 


5 


n 
n 
n      i 

D 

n 
n 
n 


5orti 


hnnnnnnnnn 


D 


R 


M 


c 
c 
c 

[I 

E 
[I 
E 
[I 


E 


H 


nU 


kU 


Q 


Dushng 

and 
Shredding 

Room 


A  -  Foreman's  Office 
B-  Flevaf-or 
C-  Scales 
^\  Red  Room 

Q-Moior 

H-Incline  Carrier 

K-QuHer 

L  -  6  -Culinaler  Dushr 

M' Incline  Carrier 

NShredoler 

O  -  6-Cy Under  Dusier 

P-  Fan  Dusier 

R  -Horrizonfal  Carrier 

S-Shrage  forShckfobeSorfed 

n  -Sorter's  Benches 

A  -Sorters 

0  -Bales 

o  -Barrels  of  Sor fed  Papers 


Fig.  :',. 


making  it  too  costly  to  sort,  he  holds  up  the  unloading  until  he 
is  further  advised  by  the  purchasing  agent  or  the  sorting-room 
foreman.  This  decreases  the  expense  of  sorting  and  increases 
the  efficiency  of  the  sorters. 

Fig.  3  represents  a  layout  of  the  bench  system  of  sorting  old 
papers.     The  sorting  benches  are  arranged  along  the  sides  of 


12  TREATMENT  OF  WASTE  PAPERS  §2 

practically  the  entire  room;  this  allows  plenty  of  space  in  the 
center  for  trucking  the  baled  and  sorted  waste  papers. 

23.  Testing  Paper  for  Mechanical  Pulp. — On  receiving  the  bale 
of  papers,  the  sorter  first  removes  the  tag,  which  she  carefully 
retains;  for  it  represents  what  the  bale  weighs,  and  her  pay  is 
based  on  this  weight,  a  common  rate  being  15  cents  per  100 
pounds.  Her  trained  eye  tells  her  at  once  how  any  particular 
bale  will  sort.  She  can  frequently  pick  out  groundwood 
(mechanical)  pulp  sheets,  which  are  termed  print,  by  the  general 
appearance  of  the  paper;  if  the  paper  is  old,  the  yellowish  color 
indicates  at  once  that  it  is  print.  As  a  further  test,  she  occasion- 
ally sprinkles  a  solution  of  aniline  sulphate  over  the  papers  as 
they  lie  on  the  bench,  the  strength  of  the  solution  being  |  pound 
of  ordinary  aniline  sulphate  to  5  gallons  of  water.  If  any  of  the 
papers  turn  yellow  after  being  sprinkled,  they  are  at  once  dis- 
carded as  print.  This  test  is  widely  known,  and  it  is  extensively 
used,  when  the  price  of  aniline  sulphate  is  normal.  When  using  a 
solution  of  the  strength  mentioned,  the  test  is  rather  slow; 
consequently,  for  a  more  rapid  test,  a  solution  composed  of  equal 
parts  of  nitric  acid  and  water  is  used  to  identify  print.  As  an 
indicator,  this  latter  solution  acts  almost  instantaneously, 
giving  a  dark  brown  color  to  print. 

Phloroglucine  is  also  a  very  satisfactory  instantaneous  indicator ; 
it  is  made  by  dissolving  1  gram  of  phloroglucinol  in  50  c.c. 
of  ethyl  (grain)  alcohol  and  25  c.c.  of  concentrated  hydrochloric 
acid;  the  solution  should  be  kept  in  an  amber-colored  bottle. 
This  solution  imparts  instantaneously  a  deep  red  coloration  to 
groundwood.  Another  rapid  test,  which  has  quite  an  extensive 
use,  is  prepared  by  making  a  strong  solution  of  caustic  soda  or 
soda  ash;  this  also  gives  a  yellow  or  brown  coloration  to  print. 

24.  The  nitric  acid  test  is  not  always  certain,  since  it  will 
give  a  brown  color  reaction  to  sulphite  also.  Hence,  when  anihne 
sulphate  is  not  to  be  obtained,  and  if  the  nitric  acid  test  is  not 
positive,  the  sorter  must  refer  to  the  foreman  (or  to  his  assistant, 
the  floorman),  whose  long  experience  enables  him  to  judge  the 
paper  in  question  by  looking  at  it  or  through  it,  tearing  it,  or  by 
trying  the  acid  test  himself.  If  there  is  any  doubt  at  all  in  his 
mind,  the  paper  is  discarded;  for,  as  previously  mentioned, 
groundwood,  or  mechanical,  pulp  will  cause  trouble  later  in 
making  a  clean  sheet  of  paper. 


§2  SORTING,  DUSTING  AND  SHREDDING  13 

25.  Rate  at  Which  Sorting  Is  Performed. — When  a  bale  has 
been  opened  and  the  sorting  begun,  if  it  appear  that  close  sorting 
will  be  required  in  order  to  remove  all  the  print  and  discards,  the 
sorter  is  required  to  work  by  the  day.  She  is  thus  enabled  to 
earn  a  fair  wage,  perhaps  $2.65  per  day.  Otherwise,  she  would 
hardly  be  able  to  sort  more  than  about  700  to  800  pounds  per 
day,  for  which  she  would  receive  not  to  exceed  $1.25. 

The  quantity  sorted  per  day,  and  the  consequent  cost  of  sorting, 
depends  directly  upon  the  quality  and  grade  of  the  papers  as 
received.  The  grades  of  waste  papers  chiefly  used  in  book-paper 
mills  are  the  following:  magazine,  book,  over-issues,  unstitched, 
lithograph,  ledger  writing,  solid  ledger  and  perhaps  some 
shavings. 

Solid  magazines  are  easily  sorted.  After  removing  the  print 
magazines,  the  names  of  which  are  well  known  to  the  experienced 
sorter,  the  deep-color  covers  of  the  selected  magazines  are  torn 
off  and  placed  in  a  container  that  receives  this  kind  of  discards. 
Solid  school  book  is  also  easily  sorted,  requiring  only  that  the  book 
backs  be  torn  off  and  the  book  divided  into  two  or  three  parts. 
Over-issues  do  not  require  sorting,  for  they  run  uniform,  and  they 
are  fed  direct  to  the  duster  by  the  conveyor;  this  is  also  the  case 
with  lithograph  and  unstitched  papers,  provided  they  are  not 
received  in  sheets  too  large  for  the  dusters  to  handle.  Solid 
ledgers  require  only  that  the  binding  be  torn  off  and  the  paper 
separated  into  suitable  thicknesses,  about  |  to  f  of  an  inch.  No.  1 
hard  and  soft  shavings  seldom  require  sorting.  On  the  above 
grades,  each  sorter  can  handle  2800  to  4000  pounds  in  10  hours, 
depending  on  her  dexterity  and  speed,  and  the  cost  of  sorting 
is  at  a  minimum,  or  15  cents  per  100  pounds. 

However,  mills  are  seldom  so  fortunate  as  to  receive  such  fine 
packings;  such  lots  come  only  occasionally.  The  usual  run  is 
No.  2  book,  magazine  and  mixed  ledger.  Although  these  lots 
are  supposed  to  have  been  graded  by  the  packers  with  due  care, 
all  sorts  of  papers  may  be  found  in  them.  The  papers  must  all 
be  handled  separately;  and  the  amount  sorted  will  vary  from 
1300  to  2500  pounds,  averaging,  usually,  about  2000  pounds  per 
sorter  per  day  of  10  hours. 

The  mixed-ledger  grade  causes  the  greatest  difficulty;  it  is 
nearly  always  sorted  by  the  day,  and  at  a  rate  of  about  $2.G5  per 
day.  In  order  that  a  sufficient  supply  may  be  on  hand  when 
necessity  demands  an  immediate  cooking  of  30,000  to  40,000  lb.. 


14 


TREATMENT  OF  WASTE  PAPERS 


§2 


5  or  6  sorters  are  constantly  employed  on  this  grade  of  stock.  It 
is  obvious  that  this  amount  could  never  be  sorted  at  short  notice 
at  a  normal  cost, 

26.  Loss  in  Sorting.— The  sorters'  discards  constitute  the  first 
shrinkage  or  loss.  All  discards  are  classified  as  follows:  Print, 
colors,  bagging,  carpets,  wrappers,  tobacco  paper,  wire  and  rope. 
For  the  period  of  a  year,  the  amounts  and  percentages  of  these 
discards  are  shown  in  the  following  table : 


Total 

Total      \°'^' 

dis-     ^'t: 

,        cards 
cards       , 

(lb.)    ^"^l: 

!  cent) 

Discards  consist  of  the  following: 

paper 

sorted 

;        (lb.) 

! 

Print      '      Colors          Backs       ^^^f""^' 
i                                              etc. 

1 
Yearly  total. ...  1 13,273,076 
Daily  average.  .  [      4.5fi90 
Monthly    aver-  i 

age 1    1,106,089 

1             1 
881,423J  6.64 
3034    6.64 

73,452    6.64 

I              1 

4.11% 
1874  lb. 

45,367  1b. 

1                    ' 
1.45%          0.25%         0.83% 
665  lb.          114  lb.           381  lb. 

16,090  1b.     2772  1b.   ;  9222  1b. 

From  the  above  table,  which  was  compiled  from  daily  records, 
the  per  cent  of  total  discards  is  6.64%;  this  is  the  first  direct 
shrinkage  in  handling  old-paper  stock,  as  it  is  supplied  to  the 
general  trade.  The  table  also  shows  that  4.11%  of  the  discards, 
or  60%  of  this  shrinkage,  is  due  to  print  or  groundwood. 
By  the  use  of  better  graded  or  better  selected  stock,  such  as  over- 
issue magazines  of  standard  qualit}^,  this  part  of  the  shrinkage 
can  be  reduced  greath'. 

27.  Containers  for  Sorted  Papers. — After  being  carefully 
sorted,  the  waste  papers  are  placed  in  barrels  or  other  suitable 
containers,  which  will  hold  100  to  150  pounds  each.  The  con- 
tainers are  placed  alongside  the  benches  of  the  sorters,  and,  when 
filled,  are  trucked  away  to  the  conveyor.  The  work  of  trucking, 
which  is  performed  by  men,  appears  to  be  quite  laborious,  ineffi- 
cient, and  an  antiquated  system;  but  it  possesses  some  good  fea- 
tures, however.  For  instance,  each  container  is  numbered  with  the 
sorter's  bench  number;  and  when  the  papers  are  thrown  upon  the 
conveyor  that  carries  them  to  the  duster,  the  two  men  who  attend 
to  this  work  carefully  examine  the  papers  for  any  discards  that 
may  be  present.  If  the  amount  thus  picked  out  runs  high,  the 
container  is  returned  to  the  sorter,  with  the  papers  that  still 
remain  in  it,  with  instructions  to  sort  it  over  again. 


§2 


SORTING,  DUSTING  AND  SHREDDING 


15 


CARRIER  SYSTEM  OF  SORTING 

28.  Description  of  Carrier  System. — By  carrier  system  of  sort- 
ing is  meant  the  process  of  handling  old-paper  stock  from  the  bale 
direct  to  the  carrier  or  conveyor;  this  sj^stem  is  illustrated  in  Fig. 
4.  Here  the  outline  a  b  c  d  e  f  represents  the  same  rooms  as 
shown  in  Fig.  3,  but  with  such  changes  in  their  arrangement  as 
will  adapt  them  to  the  carrier,  or  conveyor,  S3'stem  of  sorting 
paper  stock.  Note  the  simplicity  of  the  new  arrangement,  and 
gain  in  floor  space,  for  paper  storage. 


6  <^ "  foremani  Office 
•o  -  Elevator 
^/■Q"  ^3  =Carners 
dj-a^-dj  =Te6-l-Spratj  Barm's 

E-Toifei- 
M^  Motor 
oji  =  Inspectors 

°  -Sorters 

D  -  Bales  of 0/d  fhper^fodf 
F^^ShredderorCuj-fer  for 

LedgerJhck 
S  -SforacfefbrShck 
T  'Shrage  fbrJbrfed  Shck 


?^ 


Ci      dj 

0<=30  Oc=,0 I  Qt 


otao  0c3O0c=i& 


-^ 


Cg     ^2 


3^ 


O   QcaO   CfcaoOc^ 


if 


Z> 


E 


Fig.  4. 


The  bales  of  paper  stock  are  arranged  on  both  sides  of  the 
carrier  Ci,  C2,  Cs,  which  may  be  made  of  any  suitable  length; 
one  having  a  total  length  of  about  55  feet,  and  a  width  of  2\  feet, 
has  been  found  to  be  convenient  and  efficient.  Three  (3)  bales 
of  stock  are  placed  on  either  side  of  the  convej'or,  and  one  bale 
at  the  head  (or  starting  point)  of  the  continuous  belt.  Two 
girls  (sorters)  are  stationed  at  each  bale,  as  shown  diagram- 
matically  in  Fig.  4;  thus  14  girls  sort  7  bales  directly  onto  the  con- 
veyor. The  discards  ma}-  be  put  into  baskets  or  boxes,  or  they 
may  be  thrown  into  a  chute  under  the  carrier.  At  the  mid  point 
of  the  belts,  sprayers  c?i,  d^.,  dz,  are  placed;  these  furnish  a  con- 


16  TREATMENT  OF  WASTE  PAPERS  §2 

tinuous  fine  spray  of  a  solution  of  aniline  sulphate  or  other 
indicator  (see  Art.  23)  directly  upon  the  surface  of  the  papers, 
as  they  pass  by  on  the  conveyor.  An  elevated  barrel  of  solution, 
connected  to  a  perforated  pipe  over  the  conveyor  is  a  good 
arrangement. 

The  speed  of  the  conveyor  is  55  feet  per  minute;  and  when  the 
belt  has  traveled  20  feet  (which  takes  22  seconds),  the  indicator 
solution  will  show  the  presence  of  groundwood,  if  any  be  present  in 
the  sorted  papers.  The  use  of  this  spraying  test  is  very  necessary, 
by  reason  of  the  prevalence  of  bleached  groundwood  in  book 
papers.  Since  it  is  impossible  to  identify  bleached  groundwood 
by  eye,  it  is  necessary  to  test  every  sheet  of  paper  on  the  carrier. 
All  groundwood  book  paper  is  sent  to  the  mill  that  uses  paper 
of  this  kind.  Two  women  inspectors  are  stationed  at  the  delivery 
end  of  each  carrier;  their  duty  is  to  throw  out  any  sheet  that 
shows  the  typical  color  reaction  of  the  indicator. 

It  is  obvious  that  the  sorters  who  are  grouped  around  the 
receiving  end  of  the  carrier  cannot  use  up  too  much  time  in  close 
sorting;  they  must  keep  the  surface  of  the  carrier  completely 
covered  with  papers  at  all  times.  They  must,  therefore,  be 
able  to  sort  by  sight,  and  they  must  have  a  good  knowledge  of 
the  general  run  of  paper  stock.  Anything  that  is  groundwood, 
or  which  appears  to  be  groundwood,  or  concerning  the  nature  of 
which  there  is  any  doubt  in  their  minds,  is  at  once  thrown  out  as 
a  discard.  The  discards  thus  thrown  out  from  the  carriers  are 
then  closely  sorted  and  tested  at  the  usual  sorting  benches. 

29.  Advantages  of  the  Carrier  System. — It  has  been  stated 

that,  with  the  carrier  system,  20  girls  can  turn  out  50,000  to 

55,000  pounds,  gross  weight,  of  paper  stock  per  day  of  8  or  9  hours. 

Taking  the  lower  figure  and  assuming  that  each  girl  receives 

$2  65  X  20 
$2.65  per  day,  the  cost  per  100  pounds  is  — -^ —    =    $0,106 

=  10.6  cents.  This  may  be  compared  with  46,000  pounds,  gross 
weight,  of  paper  stock,  sorted  by  30  girls  by  the  bench  system, 
at  a  cost  of  about  15  cents  per  100  pounds. 

Further  advantages  of  the  carrier  system  are:  the  decreased 
wear  and  tear  on  the  floors;  increased  storage  space,  by  ehminat- 
ing  the  sorting  benches;  and  the  elimination  of  one-man  trucking 
barrels  and  containers,  which  are  required  with  the  bench 
system. 


§2  SORTING,  DUSTING  AND  SHREDDING  17 

DUSTING  THE  PAPERS 


MACHINERY  IN  DUSTING  ROOM 

30.  Machines  Used. — The  machinery  in  the  usual  dusting 
room  consists  of  the  conveyors,  raihoad  duster,  fan  duster,  and 
the  dust-collecting  apparatus.  For  a  capacity  of  20  tons  in  10 
hours,  all  the  necessary  power  is  supplied  by  a  35-h.p.  motor. 
Drives  for  each  of  the  above  mentioned  separate  units  are  taken 
from  a  line  shaft. 

31.  The  Railroad  Duster. — The  old  method  of  handling  papers 
consists  in  emptying  the  containers,  full  of  papers,  onto  a  con- 
veyor that  runs  at  a  moderate  speed.  Here  the  papers  receive 
a  searching  scrutiny  for  discards,  and  are  then  carried  on  a  second 
conveyor  belt,  which  moves  at  about  twice  the  speed  of  the  first 
belt.  The  second  belt  carries  the  papers  to  the  railroad  duster, 
in  which  the  papers  are  threshed,  shredded,  and  thoroughly 
separated  into  individual  sheets.  The  shredding  is  accompHshed 
by  feeding  the  papers  between  two  rolls  having  staggered  pin 
teeth.  The  general  details  of  a  railroad  duster  are  shown  in 
Fig.  4,  in  the  Section  on  Preparation  of  Rags  and  Other  Fibers. 
A  duster  of  this  type,  4  feet  in  width  and  having  6  cylinders,  has 
a  capacity  of  5000  pounds  of  waste  paper  per  hour. 

32.  The  Fan  Duster. — ^The  end  of  the  railroad  duster  empties 
into  the  fan,  or  cylinder,  duster.  One  type  of  fan,  or  cylinder, 
duster  is  shown  in  Fig.  5,  Section  on  Preparation  of  Rags  and 
Other  Fibers,  in  which  is  a  central  shaft,  with  wings,  revolving 
rapidly,  and  an  enclosing  screen  cjdinder,  which  revolves  slowly. 

The  general  action  of  a  fan  duster  is  similar  to  that  of  other 
rotary  dusters  in  use.  The  papers,  which  are  introduced  into  the 
feed  aperture  of  the  slowly  rotating  screen,  are  rapidly  struck, 
tumbled,  and  loosened  up  repeatedly  by  the  fast-revolving 
beater;  this  action  separates  the  dust  and  dirt  from  the  papers, 
which  then  fall  down  through  the  screen  to  the  bottom  of  the 
casing.  This  occurs  while  the  papers  are  progressively  beaten 
and  tumbled  along  through  the  screen,  to  be  discharged  in  a 
loose  condition. 

33.  Dusters  for  waste  papers  are  often  made  similar  to  the 
one  just  described,  but  without  the  central  shaft  and  its  wings. 
In  such  machines,  the  papers  are  moved  forward  by  making  the 


18  TREATMENT  OF  WASTE  PAPERS  §2 

screen  in  the  shape  of  a  frustum  of  a  right  cone.  The  papers  are 
fed  in  at  the  small  end  and  discharged  at  the  other  end,  usually 
upon  a  belt  conveyor  or  into  a  chute. 

34.  To  render  the  fan  duster  with  a  cylindrical  screen  capable 
of  operating  progressively  and  to  tear  the  papers  apart,  beat, 
dust,  and  freely  discharge  them  in  a  loose  condition  as  fast  as 
they  are  properl}'  fed  into  the  rotary  screen,  the  screen  is  prefer- 
ably provided  internally  with  a  series  of  projecting  bars.  The 
bars  taper,  and  those  at  the  receiving  end  are  much  larger  than 
those  at  the  discharging  end;  this  gives  virtually  a  conical  shape 
internally  to  the  screen.  The  rotating  beater  also  has  pin  teeth, 
and  its  general  outline  corresponds  to  that  of  the  screen,  though 
its  diameter  is  smaller.  In  operation,  the  beater  may  make  30 
revolutions  to  1  revolution  of  the  screen;  this  ratio  of  30:1  is  not 
fixed,  and  it  ma}^  be  considerably  greater  or  less.  When  the 
screen  is  about  10  ft.  long  and  5  ft.  in  diameter  at  the  large  end, 
and  the  beater  is  of  corresponding  size,  a  good  speed  for  the 
screen  is  8  to  10  r.p.m.  and  for  the  beater  250  to  300r.p.m.  How- 
ever, good  work  may  be  done  even  though  they  revolve  much 
faster  or  slower.  The  fan  duster  discharges  the  dusted  papers 
onto  a  conveyor  belt,  and  this,  in  turn,  delivers  them  to  the 
cooking  tanks  or  to  storage  bins. 

35.  Power  Required. — The  power  necessary  to  drive  the  con- 
veyor belts  is  estimated  to  be  1  to  2  h.p.;  for  the  railroad  duster, 
10  h.p.;  for  the  fan  duster,  5  h.p.;  and  for  the  exhaust  dust  fan, 
about  10  h.p.  These  figures  vary,  of  course,  according  to  the 
load  on  the  machines. 

36.  The  Dust. — The  exhaust  fan  is  connected  to  both  dusters ; 
it  carries  off  a  continuous  stream  of  air  that  is  laden  with  dust 
and  dirt  of  all  kinds,  which  is  conveyed  to  a  dust  collector, 
where  the  dirt  is  removed  and  the  air  is  purified  before  being 
discharged  outside.  The  amount  of  dust  removed  varies,  of 
course,  with  the  kind  of  stock  being  handled;  in  any  event,  it  is 
considered  to  be  an  inconsequential  item,  say  100  to  1.50  lb.  per 
day  in  a  plant  having  a  capacity  of  40,000  lb.  of  paper. 

A  sample  of  the  dust  was  tested.  After  being  ignited,  the 
ash  was  white  in  color  and  was  proved  to  consist  of  clay  or 
insoluble  silicate.  As  would  naturally  be  expected,  volatile 
organic  matter  constitutes  the  greatest  part  of  the  dust,  which 
really  consists  of  pure  pulp  fibers,  in  the  main,  and  would  serve 


§2  SORTING,  DUSTING  AND  SHREDDING  J9 

as  an  excellent  filler  in  certain  papers.     An  analysis  of  the  dust 
showed  it  to  contain  the  following: 

I'br  Cent 

Moisture  at  105°C 5 .  90 

Pulp  fibers 77.41 

Clay 13.13 

Alum 2 .  30 

Calcium  sulphate 1 .  25 

Total 99 .  99 


PAPER  SHREDDERS 

37.  Methods  of  Handling  Papers  for  Shredding. — Some  mills 
change  the  method  of  handhng  the  sorted  papers  from  that 
usually  followed.  In  one  instance,  in  its  endeavor  to  have  the 
paper  shredded  better,  the  mill  discards  the  use  of  the  railroad 
duster,  and  employs  a  shredder,  which  reduces  the  paper  to 
irregular  pieces,  about  4  to  8  inches  square.  The  shredder  has 
an  exhaust  fan  connected  with  it,  and  delivers  the  papers  to  a 
continuous  conveyor  rake.  The  rake  drags  the  papers  up  a 
short,  inclined,  coarse-meshed  screen,  in  which  much  of  the 
finer  and  heavier  dirt  is  sifted  out.  The  papers  then  go  from  the 
screen  to  the  fan  duster,  where  the}^  are  treated  as  previously 
mentioned. 

TYPES  OF  SHREDDERS  AND  CUTTERS 

38.  A  Popular  Shredder. — There  are  a  number  of  good  paper 
shredders  on  the  market,  and  in  use  in  various  mills,  which 
reduce  the  paper  to  a  size  that  will  quickly  absorb  cooking 
solutions.  A  short  description  of  several  of  these  machines  will 
afford  information  concerning  the  principles  made  use  of  in  their 
operation. 

Fig.  5  shows  two  views  of  a  popular  make  of  shredder.  The 
rolls  Q  open  up  the  papers  and  pass  them  to  the  shredding  rolls 
R,  which  are  cleared  by  pin  roll  P.  The  capacity  of  the  machine 
is  12  tons  of  book  stock  in  10  hours.  From  G  to  10  h.p.  will 
drive  the  machine  at  capacity,  and  no  moclianical  skill  is  required 
for  its  operation. 

39.  An  Efficient  Type. — Another  efficient  type  of  paper 
shredder   is   shown   in    Fig.    G;   it    is   running   satisfactorily  at 


20 


TREATMENT  OF  WASTE  PAPERS 


§2 


Fig.  5. 


several  plants  in  the  United  States  and  Canada.  The  machine 
is  composed  of  two  rolls  R,  having  projecting  pins  P.  One  roll 
runs  at  a  speed  of  500  r.p.m.  and  the  other  at  a  slower  speed. 
The  flywheel  F  takes  up  much  of  the  shock  and  promotes  smooth 


Fig.  6. 


§2 


SORTING,  DUSTING  AND  SHREDDING 


21 


running.  This  shredder  takes  6  to  8  h.p.  to  operate  it,  and  its 
capacity  is  4000  pounds  of  book  stock  per  hour. 

After  coming  through  the  shredder,  the  pieces  will  average 
about  2  inches  square,  and  they  are  so  well  separated  that  the 
cooking  solution  can  percolate  through  them  to  the  best  advan- 
tage. The  machine  is  automatic  in  its  action,  and  the  only  atten- 
tion it  needs  is  a  conveyor  to  carry  the  paper  to  the  hopper  H, 
at  the  top  of  the  machine,  and  to  another  conveyor  that  removes 
the  pieces  to  the  bins  or  cookers. 

40.  Stock  Cutter. — A  stock  cutter  is  shown  in  Fig.  7;  it  is 
installed  in  many  mills  for  cutting  solid  ledgers,  books  and  heavy 
magazines.     In  operation,  the  waste  paper  is  put  into  the  wooden 


Fig.  7. 

apron  box  A ;  it  is  then  carried  up  by  the  rubber  or  canvas  apron 
until  it  is  caught  by  the  large,  or  breaking-down,  feed  roll  B; 
this  roll  carries  the  paper  forward  to  the  small  feed  roll  Bi,  which 
carries  the  paper  forward  until  it  is  cut  by  four  revolving  knives 
C,  two  of  which  are  shown  in  the  illustration,  which  shear  against 
the  top  bed  knife  E.  The  stock  is  then  carried  down,  and  is 
cut  and  re-cut  by  the  four  revolving  knives  against  the  four 
cradle  knives  D.  The  weight  of  the  machine  is  8300  pounds;  it  is 
so  constructed  that  the  shock  and  jar  that  result  from  the  cutting 
of  thick  books  is  hardly  noticeable,  giving  practically  no  vibra- 
tion. Its  rated  capacity  is  a  minimum  of  2§  tons  per  hour;  but  it 
has  cut  and  handled  5  to  6  tons  per  hour,  depending  on  the 
amount  of  power  that  can  be  furnished  to  it,  and  the  length  of 
cut  desired  for  papers.     Belt  F  removes  the  cut  papers. 

41.  A  Well-known  Shredder. — Another  well-known  shredder 
is  shown  in  Fig.  8.  Here  A  is  a  roll  with  projecting  pins  P,  to 
open  the  stock,  which  is  fed  through  the  hopper  H.  The  shred- 
ding is  completed  by  blades  or  bars  B  on  roll  R,  and  the  paper  is 
delivered  at  T.  This  shredder  takes  from  5  to  15  h.p.,  depending 
on  the  size  of  the  magazines  or  books  fed  to  the  shredding  rolls. 


22 


TREATMENT  OF  WASTE  PAPERS 


§2 


Note  the  different  speeds  of  the  two  rolls,  which  is  indicated  by 
the  difference  in  size  of  the  pulleys  F  and  G.  This  machine  will 
shred  3  to  4  tons  of  magazines  per  horn".  No  repairs  or  mainte- 
nance charges  have  been  necessary  in  mills  that  have  had  this 
type  of  machine  for  as  long  as  five  j^ears,  and  no  labor  is  required 
for  attendance. 


Fig.  8. 


42.  A  Powerful  Shredder. — The  writer  visited  a  mill  that  had 
recently  installed  a  new  type  of  paper  shredder.  The  work  being 
performed  with  this  machine  was  quite  remarkable.  Large  35- 
to  40-pound  books,  from  which  the  covers  had  been  removed, 
were  fed  to  the  shredder  and  cut  into  almost  a  million  pieces,  not 
over  1  inch  square.  The  shredded  papers  are  expelled  from  the 
machine  by  a  strong  suction  of  air;  they  are  then  sent  through  a 
rotary-screen  duster  to  a  fan  duster,  which  blows  the  papers  to 
the  cooking  tanks. 

This  shredder,  shown  in  Fig.  9,  is  a  massive  machine,  weighing 
8500  lb.  The  cylinder  A  is  30  inches  long,  and  carries  20  knives 
B  (only  4  are  shown  in  the  cut)  that  cut  against  4  stationary 
knives  C,  located  under  the  lower  half  of  the  cylinder  and  set  in 
the  frame.  The  cylinder  is  36  inches  in  diameter,  and  makes  650 
to  860  r.p.m.  The  length  of  the  cutting  edge  of  the  revolving 
knives  is  6  inches,  and  of  the  stationary  knives  about  38  inches. 
Consequently,  when  the  paper  stock  is  fed  into  the  machine,  it  is 


§2 


SORTING,  DUSTING  AND  SHREDDING 


23 


cut  a  number  of  times,  and  it  is  reduced  to  a  uniform  product 
that  is  easily  handled  with  an  air  blower  through  an  18-inch 
pipe.  The  feeding  spout 
D  is  a  combination  of 
inclined  and  vertical  sides ; 
£'  is  a  conve3'or-belt  roller. 
The  power  required  to 
operate  the  machine  de- 
pends on  the  quantity  of 
paper  to  be  shredded.  It 
is  recommended  that  50 
h.p,  be  available  when  the 
production  is  3  to  5  tons  per 
hour,  and  that  about  10  h.p. 
additional  per  ton  of  in- 
creased production  per  horn- 
be  available,  up  to  the  max- 
imum capacity  of  the 
machine,  which  is  10  tons 

'  Fig.  9. 

per    hour.     Hence,     when 

operating  at  full  capacitj^,  50  -f-  (10  —  5)10  =  100  h.p.  should  be 

available,  though  not  necessarily  used.     On  the  date  of  the  visit, 


Fig.  10. 


the  machine  was  producing  4  tons  per  hour;  and  it  was  computed 
from  the  ammeter  readings  that  35  h.p.  was  being  used.  Fig. 
10  is  a  layout  of  the  conveyors  used  to  feed  this  machine  properlj'. 


24  TREATMENT  OF  WASTE  PAPERS  §2 

A  belt  conveyor  A  brings  stock  direct  from  the  waste-paper 
sorting  room  and  delivers  it  to  a  rubber-belt  conveyor  B,  which 
delivers  it  to  a  hopper  H,  from  whence  it  is  conveyed  to  the 
shredder  D.  The  papers  are  shredded  and  separated  thoroughly, 
so  that  all  impurities  will  be  removed  on  passing  through  the  fan 
duster.  A  leather  scraper  E  keeps  the  paper  from  following  the 
conveyor,  and  a  pipe  F  carries  the  dust  to  the  blower,  which 
removes  it  from  enclosure  G. 


HANDLING  SHREDDED  PAPERS 

43.  Dusting  Old  Papers  after  Shredding.^ — Strange  to  say,  the 
subject  of  dusting  the  old  papers  receives  but  scant  attention; 
it  is  usually  regarded  as  a  mechanical  process  of  dumping  old 
papers  through  the  apparatus,  and  no  further  thought  is  given 
to  it.  In  reality,  dusting  and  screening  loose  dirt  from  old  waste 
papers  by  the  fan  duster  in  the  dusting  room,  bears  the  same 
relation  to  the  resultant  finished  paper  that  removing  bark  and 
rotten  wood  from  the  pulp  wood  bears  to  the  production  of  fine, 
clean  pulp. 

To  produce  paper  free  from  dirt,  it  is  necessary  to  remove  the 
greatest  amount  of  dust  and  dirt  at  the  initial  stage  of  the  process. 
If  the  duster  delivers  thoroughly  dusted  papers,  the  subsequent 
steps  will  be  greatly  simplified.  The  cut  and  torn  papers  from 
the  shredder  should  be  given  a  thorough  dusting,  using  a  machine 
of  the  types  described  in  Arts.  31  and  32,  or  even  a  single  wire- 
screen  cylinder. 

44.  Prevention  of  Clogging. — The  variation  in  the  rate  of 
feeding  of  old  papers  to  the  dusters  is  an  important  point  to  be 
considered.  The  apparatus  is  built  for  a  certain  capacity,  say 
2500  to  4000  pounds  per  hour.  Below  the  minimum  and  up  to  the 
rated  capacity,  the  papers  are  delivered  from  the  duster  in  good 
condition;  that  is,  thoroughly  disintegrated  and  dusted.  But 
it  sometimes  happens  that  4000  to  6000  pounds  per  hour  are  forced 
through  the  machine,  causing  it  to  become  clogged,  when  it  is 
liable  to  become  dangerously  overheated,  by  reason  of  the 
increased  friction.  The  dust  cannot  then  be  properly  handled 
by  the  exhaust  fan,  and  it  fills  the  air,  making  it  almost  impossible 
to  live  in  such  an  atmosphere.     As  a  consequence,  the  papers 


§2  SORTING,  DUSTING  AND  SHREDDING  25 

will  come  out  still  dusty  and  dirty,  through  this  overburdening 
process.  To  correct  this,  the  dusting  capacity  should  be  in- 
creased, and  the  screening  area  of  the  rotary  screen  should  be 
enlarged,  to  produce  thoroughly  dusted  papers. 


PURCHASING  PAPER  STOCK 


COST  CONSIDERATIONS 

45.  Reducing  Cost  of  Sorting. — By  using  a  few  precautions,  it 
is  possible  to  reduce  the  first  cost  in  the  reclaiming  of  old  papers. 
The  first  essential  in  reducing  cost  lies  in  the  purchasing  of  old 
paper  stock.  Since  the  quality  of  the  product  of  the  mill  is 
governed  by  its  constituent  materials,  in  other  words,  by  what 
enters  into  the  composition  of  the  paper  made,  very  careful  and 
judicious  selection  of  the  waste-paper  stocks  is  a  prime  requisite. 
Orders  should  be  placed  only  with  reliable  packers,  those  that  are 
known  to  live  up  to  their  guarantee  of  doing  an  honest  business. 
It  would  be  well  to  visit  these  packers  at  their  sorting  and  packing 
rooms,  noting  the  care  they  give  to  the  handling  of  the  papers 
as  received,  their  equipment,  and  the  amount  of  business  that 
they  conduct.  Packers  should  receive  specifications  covering 
a  strictly  uniform,  clean  grade  of  papers,  and  they  should  follow^ 
out  these  orders  to  the  letter.  The  Salvation  Army  has  gone 
into  the  waste-paper  business  quite  extensively,  and  their 
packings  enjoy  the  reputation  of  being  carefully  graded  and 
free  from  groundwood.  They  command  a  higher  price  for  their 
wastes;  but  it  is  cheaper  in  the  end  to  use  their  stock,  or  to  buy  of 
similar  conscientious  packers. 

In  purchasing  paper  stock,  the  only  consideration  of  the  pur- 
chasing department  should  be  to  buy  only  that  stock  which  can 
be  recovered  to  meet  the  standard  grade  of  the  mill  and  which 
can  be  delivered  to  the  paper-machine  beaters  at  the  least  cost 
per  ton,  as  received.  The  method  of  getting  the  information 
for  purchasing  on  this  basis,  as  practiced  in  a  Wisconsin  mill,  is 
to  have  the  laboratory  or  testing  department  make  a  time, 
quahty  and  shrinkage  test  on  a  unit  lot  of  the  paper  offered  on 
the  market.  These  tests  are  then  turned  over  to  the  accounting 
department,  which  estimates  the  cost  per  finished  ton  for  the 


2C 


TREATMENT  OF  WASTE  PAPERS 


§2 


various  grades.     An  example  showing  records  of  these  tests  is 
given  below. 


' 

03 

09 

■a 

M 

"2 

o 

C 

CB    i'oQ 

tn 

o 

3 

,^ 

^ 

£ 

3 

s 

1 

SS 

d  un 
(excl 
ound 

ut  in 
ds) 

3^ 

o 

■■S 

3 
O 

3 

o 

J3 

3 

o 

O 

to  " 

fl«  ft                   ftC 

03  3 

ca-O 

03 

^^ 

•o 

*  3—                  u  2 

o  o 

o  fl 

t> 

M 

a 
3 

ta 

a 

.o 

I  5 

a 
3 

1 

M^  M            1  a  ft 

£?3 

o  ft 

o 

a 

2 

3 
o 

U5 

7^ 
i  ft 

"fl, 

•o 

•c 

^5^              £^ 

!C 

o 

o 

M 

08^^ 

fl— 

Vh/-^ 

ogja            i'SS 

^■« 

.*-^-^ 

^ 

XI 

M-  .—V 

-"S 

'a  a 

e  ft 

O   (D 

O  00 

O  « 

2  ft 

«  ft 

;Sg«       Ld^ 

s.s 

J3  > 

^"0 

II 

V  0, 

o 

o 

o 

"So 

*J  4) 
J3  > 

B 

•53  3 

1 

S 

s 

0)  a 

'S  a; 

Z 

o"" 

^- 

is- 

^ft«      ,^«= 

is" 

^'• 

^-- 

H 

P 

p 

^^ 

^^ 

57,  bags 

19i 

i 
14,  string 

A 

8780 

382.  paper 

307,  G-W  paper 

7991 

277 

102 

175 

9f 

2§ 

h 

113  5087 

9,  wire 

B 

9031 

230,  bags 
6,  wire 

20 

5,  string 
859,  G-W  paper 

7911 

268 

61 

207 

10^ 

2i 

i 

113  5217 

C 

9707 

31,  bags 

20 

269,  G-W  paper 

9386 

311 

31 

280 

m 

3 

i 

113  6353 

D 

8666 

122,  bags 
27,  wire 

19 

298,  G-W  paper 

8200 

293 

37 

256 

lOi 

3J 

J 

113 

3707 

Summary  of  Above  Tests 
(All  figures  based  on  weight  of  paper  as  shipped) 


Shrinkage  in 

Shrinkage  in 

Total 

Girl-hours 

Name 

sorting 

rest  of 

shrinkage 

per  ton  for 

room  ( %) 

process  (%) 

(%) 

sorting 

A 

8.85 

32.24 

42.09 

30.9 

B 

12.40 

29.83 

42.23 

22.2 

C 

3.31 

31.25 

34.56 

10.8 

D 

5.38 

51.85 

57.23 

15.7 

46.  Choice  of  Stock. — Only  solid  magazines,  over-issues,  un- 
stitched, school  books  and  solid  ledgers,  together  with  litho- 
graph and  shavings  should  be  used,  to  reduce  the  cost  of  sorting. 
These  grades  require  the  separating  of  the  heavy  colors  only, 
and  a  sorter  can  easily  handle  3500  to  5000  pounds  per  day.  The 
shavings  can  be  added  directly  to  the  beater,  provided  they  are 
imprinted,  and  there  is  sufficient  beater  capacity  for  completely 
brushing  out  the  fibers;  sometimes  shavings  are  first  put  through  a 
pulper.  Instead  of  trucking  the  papers  after  sorting,  they  can 
1)0  sorted  directly  onto  and  delivered  to  the  dusters  by  conveyors. 


§2  SORTING,  DUSTING  AND  SHREDDING  27 

In  place  of  tearing  magazines  and  books  by  hand,  the  work  is 
accomplished  better  and  more  quickly  by  using  machiner3^ 


IMPROVING  QUALITY  AND  USING  DISCARDS 

47.  Improving  Quality. — The  exclusive  use  of  the  grades 
mentioned  in  Art.  46  would  increase  the  quality  of  the  product, 
which  would  be  more  uniform  in  color  and  in  cleanliness.  The 
composition  of  the  stock  being  constant,  the  subsequent  cooking, 
washing,  and  bleaching  operations  would  not  be  so  variable. 
Paper  free  from  groundwood  specks  and  undissolved  ink  would 
be  obtained,  and  an  increase  in  price  of  from  50  to  75  cents  per 
hundred  pounds  could  reasonably  be  demanded.  Further, 
because  of  their  freedom  from  dirt  particles,  samples  could  be 
duplicated,  a  procedure  not  otherwise  practicable.  Finally, 
by  employing  the  cutter  for  tearing  and  shredding  these  grades 
of  papers,  the  labor  now  engaged  in  this  work  could  be  decreased 
40%  to  50%,  without  decreasing  the  output  of  the  sorting  room. 

48.  Utilization  of  Discards  from  Sorting. — The  discards, 
which  may  average  40  to  50  tons  per  month,  are  properly  sorted 
into  classes;  this  is  done  in  the  sorting  room,  and  necessitates  no 
additional  help.  The  print  is  usually  separated  into  what  is 
called  white  print  and  colored  print.  White  print  is  sold  as  such 
to  mills  making  cheap  blanks  and  liners ;  colored  print  and  heavj' 
colors  are  usually  sold  for  making  into  boards,  and  this  is  also 
the  case  with  book  backs.  Occasionally,  all  these  discards  are 
worked  over  at  the  mill  in  which  they  originate,  with  about  10% 
of  unbleached  sulphite,  which  serves  for  making  a  fairly  good 
quality  of  heavy  card  wrapping  for  shipping  rolls,  etc.  However, 
considering  the  amount  of  dirt  that  must  necessarily  enter  into 
this  grade,  and  which  pollutes  the  entire  mill  with  refuse,  it  is 
not  a  paying  procedure,  since  a  much  better  grade  of  sulphite 
fiber  wrappers  may  be  made  at  almost  the  same  cost. 

The  colors  might  be  sorted  to  each  color — such  as  blues,  reds, 
greens,  browns,  yellows — and  cooked  separately,  washed  and 
partly  bleached,  and  then  worked  over  into  colors  again.  Since 
a  majority  of  the  fibers  of  these  colored  papers  is  made  up  of 
soda  and  sulphite,  a  sheet  could  thus  be  made  that  would  sell 
for  a  good  price.  The  only  drawback  might  be  that  only  a 
limited  amount  of  stock  of  each  color  could  be  obtained,  with 
the  consequent  problem  of  disposing  of  small  lots.     Since  deduc- 


28  TREATIMENT  OF  WASTE  PAPERS  §2 

tions  are  made  for  excess  discards  when  paying  the  original  invoice 
of  the  paper  stock,  it  is  safe  to  say  that  it  is  more  profitable  to 
sell  the  discards  outright,  and  there  is  no  attendant  loss  in  doing 
this. 

QUESTIONS 

(1)  Explain   the  differences  in  the  layouts  for  bench  sorting  and  fcr 
carrier,  or  conveyor,  sorting. 

(2)  What  chemicals  are  used  to  detect  the  presence  of  mechanical  pulp  in 
waste  papers? 

(3)  About  how  much  dust  is  obtained  from  the  dusting  of  waste  papers? 

(4)  Why  is  it  unwise  to  overload  the  dusters  that  handle  the  cut  and 
shredded  stock? 

(5)  How  can  the  purchasing  department  help  the  superintendent  to  get 
better  results  from  the  treatment  of  waste  papers? 


COOKING,  DE-INKING  AND  DE-FIBERING 


COOKING  PROCESSES 


OPEN-TANK  PROCESS 

49.  Methods  of  Cooking.^ — The  methods  for  cooking  and 
de-inking  old  waste  papers  that  are  now  in  use  are  few  in  number, 
insofar  as  the  principles  utilized  are  concerned.  However, 
each  mill  usually  employs  certain  variations,  which  it  considers 
necessary  for  the  successful  treatment  of  waste-paper  stock. 
The  three  oldest  methods  in  use  are:  (a)  Cooking  in  open-  or 
closed-top  stationary  tanks;  (6)  cooking  in  cylindrical  or  globe 
rotary  boilers;  (c)  cooking  in  horizontal-circulating  cooking 
engines.     These  processes  will  now  be  discussed. 

50.  Cooking  in  Open  Tanks. — This  is  by  far  the  most  usual 
method  of  cooking  old  waste  papers;  it  is  used  extensively  in  a 
number  of  the  older  mills.  It  is  designated  the  open-tank 
process  because  the  cooking  tank  is  not  covered  while  the  papers 
are  being  cooked.  Most  mills  that  use  this  process  have  their 
own  ideas  regarding  the  details,  such  as  the  strength  of  cooking 
liquor,  time  of  cooking,  kind  of  alkali  to  use,  and  temperature  of 
the  cooking  liquor,  and  these  differ  very  materially  from  the 
details  of  the  original  Ryan  process  (see  Art.  8).     These  differ- 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        29 


ences  are  the  result  of  many  years  of  experience;  and  the  mills 
have,  by  degrees,  reached  the  point  where  they  now  have  sound 
data  for  properly  cooking  old  paper  stock. 

51.  The  Cooking  Tank.— The  cooking  tank,  or  bleach  tub,  as 
it  is  usually  termed,  is  a  stationary  cyhndrical  tank  B,  Fig.  11, 
built  of  Y^-inch  boiler  plate; 
it  is  10  feet  deep,  10  feet  in 
diameter  at  the  bottom,  and 
10  feet  1  inch  in  diameter  at 
the  top.  The  plates  are  riv- 
eted so  that  all  projections 
will  be  on  the  outside,  in 
order  to  make  the  inside  as 
smooth  as  possible.  The  tank 
is  provided  with  a  solid 
bottom  C  and  a  false  bottom 
D.  The  false  bottom  is  made 
of  iVinch  boiler  plate,  and  in 
8  sections,  4  of  which,  Di,  D^, 
Dj,  Di,  are  shown  in  the 
illustration.  To  enable  the 
cooking  liquor  to  filter 
through  to  the  real  bottom, 
these  sections  are  perforated 
with  ^-inch  holes,  spaced  3 
inches  apart  from  one  an- 
other. This  false  bottom 
rests  on  a  cast-iron  spider, 
which  has  8  arms  Fi,  Fo,  etc. 
The  spider  rests  on  an  octa- 
gonal framework  of  wooden 
blocks  Gi,  Go,  etc.,  6  inches 
square  in  cross  section.  The 
space  between  the  two  bot- 
toms serves  to  contain  a  large 
volume  of  liquor,  which  is 
forced  up  the  8-inch  central 
pipe  77  by  a  steam  injector  K,  when  the  cooking  is  in  process.  The 
arms  of  the  spider  are  riveted,  or  otherwise  fastened,  by  a  flange 
L  to  the  central  pipe  H.  The  top  of  the  central  pipe,  which  is 
about  9  feet  long,  is  equipped  with  a  baffle  plate  P,  10  inches  in 


FiG.Jll. 


30  TREATMENT  OF  WASTE  PAPERS  §2 

diameter,  the  under  side  of  which  is  slightly  concaved.  The  baffle 
plate  is  so  designed  that  the  liquor  striking  it  is  sprayed  out- 
wards and  downwards,  thus  covering  the  entire  exposed  surface 
of  the  stock  in  the  tank  with  a  shower  of  liquor.  Near  the  top 
of  the  pipe  is  a  U-shaped  hook  or  bale  R,  of  l|-inch  round  steel,, 
fastened  by  bolt  S,  for  attaching  hook  T  of  the  hoisting  mechan- 
ism; hook  R  is  allowed  to  swing  downwards  when  not  in  use. 
V  is  a  Ij-inch  steam  inlet,  Vi  is  a  l|-inch  pipe,  V2  is  a  1^-inch 
plug  valve  for  drain,  and  X  is  a  4-inch  washout  valve. 

The  lifting  mechanism  is  supported  conveniently  by  erecting 
a  pier  or  column  on  either  side  of  the  tank.  A  spur  shaft  carries 
two  sets  of  pulleys,  one  for  raising  the  spider  slowly  and  the  other 
for  lowering  it  rapidly.  The  pulleys  are  belted  to  a  main  shaft 
that  is  situated  at  a  convenient  distance  from  the  spur  shaft. 
One  open  and  one  crossed  belt  are  used.  The  spur  shaft  carries  a 
bevel  pinion  that  meshes  with  a  large  bevel  gear,  which  turns 
like  a  nut  on  the  long  screw  A,  and  lifts  or  lowers  the  spider. 
Over  each  tank  is  placed  a  hood,  which  has  a  vent  for  carrying 
off  the  steam  and  fumes. 

52.  Furnishing  the  Papers. — After  being  thoroughly  dusted, 
the  papers  are  discharged  onto  a  conveyor  belt,  which  carries 
them  to  another  belt  on  the  floor  above  the  cooking  room;  this 
latter  belt  brings  the  papers  to  chutes,  which  may  be  arranged  to 
deliver  the  papers  directly  into  the  tanks;  or  the  papers  may  be 
charged  in  armfuls  at  a  time,  by  two  men.  This  latter  method 
may  at  first  appear  to  involve  extra  labor  and  time;  nevertheless, 
it  is  the  better  method,  because  of  the  more  uniform  distribution 
of  stock. 

53.  Furnishing  and  Heating  the  Liquor. — Before  beginning  to 
furnish  (charge)  the  papers,  the  liquor  is  made  up  to  strength, 
and  the  correct  volume  of  liquor  is  added  to  the  cooking  tanks. 
It  is  then  heated,  by  injecting  steam  under  the  false  bottom,  to 
about  200°-210°F.  At  this  temperature,  the  liquor  is  forced  up 
the  central  pipe  and  against  the  baffle  plate,  and  is  sprayed  out- 
wards and  downwards,  in  a  full  circle,  over  the  entire  upper 
surface  of  the  stock.  The  spraying  process  is  intermittent;  it 
occurs  only  when  the  pressure  of  the  steam  under  the  column 
of  liquor  in  the  central  pipe  overcomes  the  weight  of  the  volume 
of  this  liquor  in  the  pipe,  and  projects  it  upwards  against  the 
baffle  plate;  and  it  continues  until  the  excess  pressure  falls  and 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        31 

becomes  zero.  The  liquor  then  filters  through  the  papers  or 
runs  down  the  sides  of  the  pipe  or  the  tank,  returns  to  the 
bottom,  and  forms  a  new  and  cooler  (also  heavier)  volume  of 
Uquor  for  the  steam  pressure  to  work  against. 

54.  Dry  Cooks. — The  spraying  action  should  be  so  regulated 
as  to  occur  about  4  to  6  times  a  minute  during  the  period  that  the 
papers  are  being  cooked.  Evidently,  this  spraying  must  occur 
more  frequently  while  the  papers  are  being  furnished  to  the 
tanks,  and  it  is  then  increased  to  about  10  to  15  times  per  minute. 
For  this  reason,  some  mills  decidedly  oppose  continuous  furnish- 
ing of  papers  direct  from  the  chutes.  They  claim  that  papers 
falling  continuously  are  not  evenly  distributed  around  the  tank, 
that  they  are  liable  to  become  bunched  'or  packed,  forming 
pockets  of  dry  papers  that  do  not  come  into  contact  with  the 
spraying  liquor.  This  results  in  what  is  termed  a  dry  cook  or 
bad  bleach;  the  ink  is  not  acted  upon,  the  sizing  of  the  papers  and 
the  oily  vehicles  of  the  ink  are  not  thoroughly  saponified,  and 
on  the  later  washing  of  the  papers,  it  is  impossible  to  wash  off 
all  the  ink  and  secure  a  clean,  white  pulp. 

In  addition  to  the  presence  of  the  ink  particles,  another  bad 
feature  of  a  dry  cook  is  that  the  paper  itself,  by  not  coming  in 
contact  with  the  liquor,  will  not  be  entirely  reduced  to  a  pulpy 
mass  in  washing,  and  it  will  not  be  thoroughly  brushed  out  during 
the  short  treatment  it  receives  in  the  beaters.  Still,  a  consider- 
able percentage  is  fine  enough  to  pass  lengthwise  through  the 
machine  screens;  and,  on  being  made  into  paper  and  calendered, 
these  dry  particles  cause  a  mottled  or  blocky  appearance  in  the 
finished  paper.  These  troubles  are  attributed  to  the  method  of 
scattering  the  papers  across  the  top  of  the  tank.  The  remedy  is  to 
furnish  the  papers,  particularly  hard-sized  ledger  and  lithograph, 
in  scattering  armfuls;  the  papers  are  thus  ovenlj^  distributed,  and 
they  all  become  saturated  with  the  spraying  liquor  before  the 
next  armful  is  thrown  in  the  same  place.  With  soft-sized  maga- 
zine and  book  stock,  the  papers  may  be  delivered  from  the  chutes 
directly  into  the  tanks;  they  are  then  raked  and  distributed 
evenly  over  the  path  of  the  spraying  liquor  by  two  men,  one  on 
either  side  of  the  tank. 

55.  Preparation  of  Cooking  Liquor. — In  preparing  a  new  cook- 
ing liquor,  or  fresh  bleach,  1200  pounds  of  soda  ash  are  dissolved  in 


32  TREATIMENT  OF  WASTE  PAPERS  §2 

water,  heated,  and  agitated  until  thoroughly  dissolved;  sometimes 
the  equivalent  in  caustic  soda  is  used  instead  of  soda  ash.  This 
operation  is  carried  on  in  the  alkali  room,  on  the  floor  directly 
above  the  cooking,  or  bleacher,  room.  The  liquor  is  run  from 
the  dissolving  tank  into  the  cooking  tank,  which  has  previously 
been  cleaned  out  and  made  ready  for  the  new  alkali  liquor. 
Fresh  water  is  turned  into  the  cooking  tank  until  it  reaches  a 
depth  of  4|  feet;  with  a  tank  10  feet  in  diameter,  this  is  equivalent 
to  a  volume  of  2644  gallons,  or  a  strength  of  liquor  containing 
1200  -^  26.44  =  45.4  pounds  of  soda  ash  to  100  gallons  of  cooking 
hquor.  With  a  hydrometer,  this  liquor  should  test  9.15°Tw.  or 
6.34°Be.,  at  60°F.;at  180°F.,  which  is  the  temperature  at  which 
the  mill  test  is  usually  made,  the  reading  should  be  3.15°Tw.  or 
2.24°Be. 

This  strength  of  liquor  will  thoroughly  cook  6000  lb.  of  ordinary 
soft-sized  book  and  magazine  paper.  After  long  years  of  practice, 
this  amount  of  alkali  has  been  observed  to  produce  the  best 
results,  and  it  is  taken  as  the  standard  for  this  grade  of  stock. 
For  cooking  hard-sized  ledger  and  deep-colored,  hard-sized 
lithograph  papers,  the  strength  of  liquor  customarily  used  is 
6.9°Be.  or  10°Tw.  at  180°F. ;  this  reduced  to  60°F.  gives  a  reading 
of  10.7°Be.  or  16°Tw.  This  reading  is  equivalent  to  7.57%  of 
soda  ash  by  weight,  or  1750  pounds  of  soda  ash  is  required  to  be 
used  to  give  this  test. 

While  this  amount  of  alkali  is  excessive,  it  is  not  considered 
economical  to  reduce  it;  because  the  cooked  papers  might  then 
show  defects  of  one  kind  or  another,  and  these  would  at  once  be 
attributed  to  the  way  the  paper  was  furnished  and  to  the  wrong 
strength  of  liquor  used. 

56.  Before  allowing  the  papers  to  be  cooked  over  night,  the 
liquor  is  again  tested.  A  sample  is  taken  while  the  liquor  is  being 
sprayed  over  the  papers,  and  hydrometer  and  thermometer 
readings  are  also  taken.  By  referring  to  the  scale  of  corrections 
for  the  temperature,  it  is  an  easy  matter  for  the  alkali  man  to 
ascertain  whether  or  not  the  liquor  is  up  to  the  required  strength; 
if  not,  he  at  once  adds  more  of  the  alkali  solution.  All  the  liquors 
are  tested,  and  the  results  are  recorded  on  the  daily  report  sheets, 
together  with  the  amount  of  alkali  used  for  each  cooking. 

57.  Duration  of  Cook. — The  operation  of  filling  each  tank 
usually  takes  I5  to  2  hours  to  furnish  6000  pounds  of  paper.     This  is 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        33 

allowed  to  cook  from  5  to  10  hours,  even  15  hours,  at  times.  Light 
book  and  magazine  can  be  thoroughly  cooked  in  7  hours,  which  is 
the  minimum  length  of  time  in  which  it  is  possible  to  obtain  good 
results.  When  there  is  a  shortage  of  paper  stock,  a  tank  is  hurriedly 
furnished  and  is  cooked  for  5  hours,  but  the  results  are  far  from 
satisfactory.  Although  most  of  the  ink  will  have  been  acted  upon, 
a  small  percentage  will  sometimes  remain  uncooked,  and  this  will 
reduce  the  quality  of  the  resultant  sheet. 

For  most  of  the  hard-sized  ledgers  and  colored  lithograph 
papers,  10  to  12  hours  is  considered  sufficient,  though  if  time  is 
available,  that  is,  if  there  is  a  large  quantity  of  cooked  papers 
ahead  of  the  washers,  the  cooking  time  is  increased  considerably, 
even  to  15  hours.  This  length  of  time  is  possible,  if  the^papers 
are  furnished  in  the  first  tank  filled  in  the  morning;  the  tank  will 
be  filled  by  9  a.m.,  and  the  papers  are  ready  to  be  taken  off  by 
midnight. 

58.  Steam  Used  in  Cooking. — The  amount  of  steam  used  in 
the  cooking  of  the  papers  is  an  important  factor  in  estimating 
the  cost  of  the  process;  but  no  definite  data  have  been  obtained 
as  yet  regarding  the  amount  consumed.  The  pressure  on  the 
main  steam  line  is  reduced  by  a  valve  to  30  pounds,  the  steam 
flowing  through  a  l|-inch  pipe  to  each  cooking  tank.  Here  the 
pressure  is  again  reduced  by  a  valve,  and  the  amount  of  steam 
used  is  regulated  by  the  number  of  intermittent  showers  or 
sprayings  of  liquor  that  are  desired  per  minute. 

That  the  amount  of  steam  used  is  excessive,  is  admitted  by  all 
those  who  have  inspected  the  system.  At  times,  after  all  the 
liquor  has  been  sprayed  up,  it  fails  to  return  quickly  enough  to 
form  a  seal  below  the  false  bottom,  for  the  steam  to  work  against; 
the  result  is  that  live  steam  continues  to  be  injected  upwards 
into  the  open  air  until  this  seal  is  again  formed.  In  a  few  mills, 
in  order  to  retain  the  heat  of  the  steam,  the  tanks  are  encased  with 
wood  or  with  an  asbestos  covering. 

59.  Reducing  Steam  Consumption. — To  reduce  the  amount  of 
steam  used,  it  was  suggested  that  the  tank  be  covered  with  a 
wooden  or  iron  cover  while  the  cooking  was  in  progress.  An 
opening  1  foot  square  was  made  in  the  cover,  about  1  foot  from  the 
edge,  and  to  this  was  attached  a  wooden  outlet,  which  conducted 
the  steam  and  vapor  outside  the  building.  While  this  arrange- 
ment reduced  very  materially  the  amount  of  steam  used,  it 


34  TREATMENT  OF  WASTE  PAPERS  §2 

caused  other  troubles,  due  to  excess  condensation,  etc.,  and  it  was 
discontinued. 

One  fact  noted  while  using  the  cover  on  the  tank,  was  the  great 
difference  in  the  amount  of  heat  remaining  in  the  papers,  when 
they  were  ready  to  be  taken  off.  The  papers  in  the  tank  were  so 
hot  that  it  was  necessary  to  allow  the  cook  to  stand  and  cool  off, 
until  the  other  cooks  had  been  removed  from  their  tanks.  Even 
then,  the  papers  were  removed  only  with  the  greatest  difficulty 
and  discomfort. 

Although  the  increase  in  the  amount  of  heat  retained  by  the 
papers  adds  to  the  difficulty  of  handling  them  after  cooking,  the 
heat  hastens  the  saponification  action;  the  ink  is  more  completely 
broken  up  and  dissolved,  and  it  is  more  easily  washed  out  in 
the  washers;  the  tendency  of  the  ink  to  collect  into  small  lumps 
is  overcome,  because,  after  being  subjected  to  the  continued 
heat  action,  the  particles  of  ink  are  very  finely  subdivided  and 
will  more  readily  form  an  emulsion  with  the  cooking  liquor. 
Also,  since  more  than  two-thirds  of  the  hotter  liquor  is  recovered, 
and  much  more  drains  away  while  the  papers  are  in  storage,  the 
subsequent  washing  time  for  the  papers  is  lessened  considerably. 

60.  Removing  the  Cooked  Papers. — After  the  papers  have 
been  allowed  to  cook  the  required  length  of  time,  the  cooked 
papers  are  raised  by  a  hoisting  device  that  lifts  the  false  bottom 
from  the  tanks.  The  hoisting  mechanism  is  located  on  the  floor 
above  the  cooking  room.  A  25  h.p.  motor  will  furnish  sufficient 
power  to  raise  five  cooks  at  the  same  time. 

When  the  false  bottom  has  been  raised  to  within  6  inches  of 
the  top  of  the  tank,  it  is  stopped;  the  papers  are  allowed  to  cool, 
and  the  liquor  drains  back  into  the  tank.  Two  men  clad  in  the 
scantiest  attire,  consisting  usually  of  overalls  and  wooden  shoes, 
mount  to  the  top  of  the  papers  and  shovel  them  off  with  pitch- 
forks into  large  cars  or  containers,  which  are  grouped  around  the 
sides  of  the  tank.  The  work  is  laborious;  it  is  also  distaste- 
ful, because  the  steam  that  continuall}'' arises  is  filled  with  peculiar 
odors  from  the  papers.  It  usually  takes  2  hours  to  fork  off 
6000  pounds  of  the  cooked  papers,  and  the  working  time  is 
limited  to  5  hours  for  each  man;  the  cost  of  handling  the  cooked 
papers  is  quite  small. 

61.  Other  Methods  of  Removing  Papers. — A  method  of 
removing  the  cooked  papers  that  has  been  tried  and  found  to 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        35 

be  very  satisfactorj^,  is  to  attach  4  vertical  rods,  spaced  equally 
distant  apart  around  the  false  bottom;  when  the  cook  is  raised, 
these  rods  form  a  kind  of  basket,  and  may  be  suitably  fastened  to 
an  arrangement  that  will  allow  the  entire  mass  of  papers,  still 
remaining  on  the  false  bottom,  to  be  swung  clear  of  the  tank, 
onto  a  track  system,  and  moved  either  by  a  crane  or  pulle}^  over 
to  a  draining  pit.  The  false  bottom  is  so  built  in  this  case  that 
it  permits  dumping  by  turning  on  hinges.  After  draining  in  the 
pit  for  some  time,  the  papers  may  be  fed  into  a  hopper  or  kneader, 
located  below  the  pit,  which  will  so  condition  the  papers  that 
they  can  be  pumped  to  the  washers. 

To  accomplish  this  work  with  fewer  men,  one  enterprising 
mill  has  laid  a  small,  narrow-gauge,  track  system,  sunk  in  a 
concrete  foundation.  The  tracks  extend  from  the  tanks  to 
each  washer  in  the  beater  room,  and  to  side  tracks  in  the  bleacher 
room;  the  latter  serve  to  store  papers  ahead  of  the  washer.  By 
means  of  this  track  system,  with  small  cars  made  to  fit  the  rails, 
one  or  two  men  can  easily  convey  the  cooked  papers  to  the 
washers.  Some  mills  have  an  electric  truck,  which  has  an  arm 
that  is  run  under  the  box  of  stock,  lifts  it,  and  carries  it  anywhere, 
with  no  manual  labor  at  all. 

62.  Recovery  of  Chemicals. — The  recovery  of  the  alkaline 
cooking  liquor  used  in  the  open-tank  process  is,  perhaps,  the 
best  point  in  favor  of  this  method  of  cooking  old  paper  stock. 
The  fact  that  no  additional  care,  expense,  or  trouble  is  incurred 
in  effecting  the  recovery  of  the  liquor  is  also  an  attractive  feature. 
Moreover,  the  cooking  of  paper  stock  is  not  nearly  so  satis- 
factory when  done  with  fresh  liquor  as  it  is  when  part  recovered 
Hquor  and  part  fresh  liquor  are  used,  because  the  soap  or  saponi- 
fied oil  that  is  contained  in  the  recovered  liquor  has  a  definite 
and  essential  function  to  perform  in  emulsifying  the  carbon  black 
and  removing  it  in  washing. 

The  rate  of  ascent  during  the  raising  of  the  false  bottom  carrying 
the  cooled  papers,  is  very  slow;  it  generally  takes  30  min.  to  lift 
the  papers  10  feet.  This  is  a  lifting  speed  of  only  4  in.  per  min. ; 
and  it  is  so  slow  that  nearly  all  the  liquor  not  absorbed  by  the 
papers  finds  its  way  to  the  remaining  liquor  in  the  tank.  By 
thus  slowly  draining  and  running  ofif  the  liquor,  a  varying  per- 
centage of  the  liquor  is  saved.  The  degree  of  variation  depends 
upon  the  nature  of  the  papers,  the  soft,  porous  papers  acting 
Hke  a  spongy  mass  to  retain  more  liquor  than  the  hard-sized. 


36  TREATMENT  OF  WASTE  PAPERS  §2 

stiff,  rag-stock  papers.  Another  cause  for  variation  is  the  loss  of 
liquor  due  to  splashing  over  the  side  of  the  tank  while  spraying 
with  too  great  pressure  of  steam; also,  when  raising  the  papers,  the 
liquor  continues  to  ooze  out  of  sides,  and  drains  down  to  the  rim 
of  the  top  of  the  tank.  If  there  is  no  opening  by  which  the 
liquor  can  return  to  the  tank,  it  will  run  over  the  sides  and  be  lost 
in  the  drain  to  the  sewer.  However,  with  all  these  losses,  the 
average  daily  recovery  is  about  66f  %  of  the  liquor  used.  In  some 
cases,  the  recovery  has  been  as  low  as  24%  and  as  high  as  92%. 

63.  Losses  in  Recovery. — Figures  tabulated  from  exact  data, 
to  show  the  variation  in  the  percentage  recovery  of  liquor  that 
occurs  from  day  to  day  under  ordinary  conditions,  with  seven 
tanks  in  use,  indicated  a  maximum  variation  of  33.4%  to  88.9% 
of  recovered  liquor.  The  monthly  averages  ran  from  66.00% 
to  78.03%.  Two  tanks  were  furnished  with  new  liquor  during 
this  period.  The  average  recovery  of  soda-ash  liquor  on  all 
tanks  was  71.34%,  with  146  cooks. 

In  this  tabulation,  the  variation  was  quite  evident.  At  first, 
it  was  thought  that  the  highest  recovery  figure,  88.9%,  did  not 
represent  the  same  value  as  the  corresponding  volume  or  per  cent 
of  new  liquor.  It  was  claimed  that  from  20%  to  30%  of  the 
alkali  content  was  consumed  in  the  saponification  of  the  ink, 
colors,  and  sizings,  and  that  the  condensation  of  the  steam  caused 
the  increase  in  the  volume  of  the  liquor.  It  is  true  that  there 
is  some  decrease  in  the  strength  of  the  alkali  content  of  the  liquor 
by  saponification;  there  is  likewise  considerable  condensation 
while  the  liquor  is  being  raised  to  the  boiling  point,  though  after 
that,  the  steam  acts  only  as  a  projecting  force  to  spray  the  liquor. 
The  volume  of  steam  and  vapor  given  off  on  spraying  is  about 
equal  to  the  amount  of  steam  injected  into  the  tank. 

As  previously  stated,  there  is  a  loss  of  liquor  over  the  tanks  in 
spraying,  and  in  the  liquor  that  oozes  from  the  sides  of  the 
papers,  while  being  raised,  which  fails  to  return  to  the  tanks. 
There  is  a  further  loss  in  the  liquor  that  drains  away  while  the 
cars  are  standing  in  storage.  All  this  liquor,  which  now  goes  to 
the  sewer,  could  be  very  easily  saved  and  recovered,  and  at  slight 
cost.  A  concrete  flooring,  with  grooved  drains,  would  conduct 
all  this  liquor  to  a  common  catch-all  tank.  A  catch  pan  could 
be  riveted  to  the  top  of  the  cooking  tank,  into  which  would  drain 
all  the  liquor  that  ordinarily  goes  to  waste  when  the  papers  are 
raised. 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        37 

64.  Increasing  Recovery  by  Washing. — The  percentage  of 
alkah  recovered  could  be  further  increased  by  washing  the  papers 
once  or  twice  with  warm  water,  while  they  still  remained  in  the 
cooking  tank.  This  would  necessitate  draining  off  the  liquor 
from  the  tanks  before  adding  the  wash  water,  in  a  manner  similar 
to  that  of  washing  chemical  pulp.  But  this  is  not  desirable, 
since  the  soapy  liquor  sticking  to  the  papers  acts  to  remove  the 
carbon  black,  when  put  into  the  washing  engine.  The  strong 
liquor  should  be  stored  separately,  and  the  wash  water  should  be 
stored  by  itself  in  another  tank;  in  this  way,  with  a  little  care 
and  attention,  the  strength  of  the  liquors  in  all  the  tanks  would 
be  the  same.  The  strength  of  the  recovered  liquor  could  be 
determined,  and  its  volume  readily  ascertained.  Then,  by  using 
the  wash  water  to  dissolve  the  correct  amount  of  soda  ash,  and 
adding  to  the  strong  liquor,  the  strength  and  volume  of  the 
mixture  could  be  brought  up  to  the  standard  strength  for  cooking. 


ROTARY-BOILER  PROCESS 

65.  Reasons    for    Using    the    Rotary-Boiler    Process. — The 

cooking  of  old-paper  stock  in  rotary-cylindrical  and  rotary- 
globe  boilers  is  a  later  development  that  is  viewed  with  great 
favor  by  all  the  newer  mills.  The  cleanliness  of  the  cooking  room, 
the  absence  of  steam  and  condensation,  and  the  ease  with  which 
the  cooked  papers  are  handled,  are  the  great  assets  of  this  method. 
The  claim  is  also  made  that  it  is  a  much  more  economical  process. 

Although  the  saving  in  labor,  both  in  filling  the  rotaries  and  in 
the  subsequent  washing  operations,  represents  a  very  good  return 
on  the  investment,  the  chief  argument  in  favor  of  the  rotary 
sj^stem  is  the  uniformity  of  the  cooked  product. 

The  general  arrangement  of  a  cylindrical  rotary  boiler  installa- 
tion is  shown  in  Fig.  12.  Details  of  the  boiler  are  given  in  the 
Section  on  Treatment  of  Rags,  etc. 

66.  Discussion  of  the  Process. — The  preliminary  sorting  and 
dusting  is  much  the  same  as  in  the  open-tank  process.  A  few 
mills  have,  very  wisely,  added  cutters  or  shredders  to  their 
equipment,  which  help  to  condition  the  papers  for  the  best 
results  in  cooking.  The  tendency  for  the  papers  to  roll  up  into 
thick  wads,  caused  by  the  slow,  revolving  motion  of  the  boiler, 
sometimes  gives  trouble.     These  thick  wads  of  paper  are  not 


38  TREATMENT  OF  WASTE  PAPERS  §2 

thoroughly  saturated  with  steam  and  cooking  liquor,  and  the 
result  is  the  same  dry  cook  mentioned  in  Art.  54.  To  avoid 
this,  the  papers  are  first  cut  into  short  strips  or  are  shredded 
into  irregularly  shaped  pieces,  that  they  may  come  more  readily 
into  contact  with  the  liquor,  and  not  roll  up  into  wads. 

However,  improvement  in  the  design  of  the  rotary-cylindrical 
boiler  in  the  last  few  years,  has  overcome  the  tendency  of  the 
stock  to  roll  up,  or  ball  up,  into  dry  wads.  Investigation  has 
shown  and  practice  has  proved  that,  by  increasing  the  number 
of  the  internally  projecting  pins  and  by  staggering  and  placing 
them  in  proper  positions,  the  rotary  will  not  only  cook  thoroughly 
but  it  will  also  act  as  a  de-fibering  machine.  In  the  8  X  24-foot 
rotary,  the  present  practice  calls  for  a  varying  number  of  these 
rag  or  de-fibering  pins,  which  are  usually  arranged  in  5  to  9 
rings  of  8  pins  each,  the  8  pins  being  spaced  uniformly  about 
the  circumference.  The  pins  are  made  of  |  X  l|-inch  iron,  bent 
to  the  shape  of  a  U,  and  9  in.  high;  they  are  riveted  to  the  shell. 
The  specifications  formerly  in  use  designated  only  about  9  or  10 
of  these  pins.  One  mill  that  is  equipped  with  this  new  type  of 
rotary  reports  that  it  has  abandoned  entirely  the  use  of  cutters 
and  shredders,  and  that  it  has  even  eliminated  the  railroad 
duster  and  the  fan  duster  in  its  sorting  and  dusting  rooms. 
Instead  of  using  a  50-  to  60-h.p.  motor  to  drive  the  sorting- 
room  equipment,  as  formerly,  a  small  5-  to  10-h.p.  motor  now 
handles  the  load  of  the  three  or  four  sorting  carriers,  the  papers 
are  conveyed  in  their  original  condition  directly  to  the  rotaries, 
and  a  heavier  cook  can  be  handled.  The  charge  has  been 
increased  from  7500-9000  pounds    to  12,000-14,000  pounds. 

Without  a  doubt,  the  older  rotaries  could  not  have  accom- 
phshed  what  those  of  the  newer  type  have  done.  It  is  a  question, 
however,  whether  good  judgment  was  exercised  in  discarding 
the  dusting  equipment  at  the  mill  above  referred  to.  Dirt  must 
be  taken  out  some  time;  and  the  proper  place  is  where  the  papers 
are  dry  and  are  in  their  original  condition.  Bearing  in  mind 
that  the  purpose  of  this  mill  was  to  keep  the  paper  stock  as  flat 
and  as  compact  as  possible,  the  use  of  a  revolving,  tapering, 
cylindrical-screen  duster  would  remove  the  surface  dust  by  a 
tumbling  action,  and  it  would  add  but  little,  if  anj^thing,  to  the 
bulk  of  the  paper  stock  entering  the  rotary  boiler. 

67.  Fig.  12  shows  the  relative  positions  of  the  rotary  and  the 
dumping  pit.     Here  R  represents  a  typical  8  X  24-foot  rotary;  T 


§2        COOKING,  DE-INKING  AND  DE-FIBEIUNG        39 


40  TREATMENT  OF  WASTE  PAPERS  §2 

and  T,  the  trunions,  or  bearings,  one  of  which  is  hollow,  for 
admitting  steam;  G,  the  motor  driving  gear;  P,  the  dumping  pit; 
F,  the  discharge  connection.  View  (c)  shows  the  agitator 
device  A,  used  in  modern  pits  for  dumping  of  stock,  and  its  drive. 

68.  Furnishing  the  Rotary. — After  being  discharged  from  the 
dusters  onto  a  conveyor  belt,  the  papers  are  delivered  in  a  con- 
tinuous stream  to  the  manhole  opening  of  the  boiler.  There  is  a 
difference  of  opinion  in  regard  to  the  correct  procedure  for 
furnishing  the  papers  and  the  liquor.  In  one  mill,  the  practice 
is  to  furnish  the  papers  first,  packing  them  with  long  iron  prod- 
ding rods;  the  liquor  is  then  run  in  all  over  the  papers.  It  is 
claimed  that  by  this  method  the  papers  are  more  uniformly 
acted  on  by  the  liquor;  also,  opportunity  is  afforded  for  packing 
the  papers,  so  they  will  not  tend  to  float  when  the  liquor  is 
added,  thereby  decreasing  the  capacity  of  the  boiler. 

A  second  method  in  vogue  is  to  furnish  the  papers  and  liquor 
together.  In  this  way,  it  is  thought  that  the  papers  are  more 
thoroughly  soaked  with  the  liquor,  and  the  possibility  of  a  dry 
cook  is  overcome;  also,  the  total  time  for  filling  the  rotary  is 
diminished,  which  is  a  valuable  factor  in  costs  and  production. 

A  third  method  consists  in  running  in  the  required  volume  of 
soda-ash  solution  first,  and  then  furnishing  the  papers.  The 
argument  in  favor  of  this  method  is  that  there  will  be  absolutely 
no  dry  spots  in  the  papers,  and  a  much  cleaner  pulp  will  result, 
with  a  thorough  cooking. 

69.  Amount  and  Strength  of  Liquor. — ^A  rotary  boiler  8  feet  in 
diameter  and  24  feet  long  is  considered  to  be  of  the  most  efficient 
size  for  cooking  old  papers.  A  boiler  of  this  size  has  a  capacity 
of  1200  cu.  ft.,  and  it  will  hold  from  5  to  7  tons  of  dry  paper 
stock,  depending  on  the  grade  and  condition  of  the  papers. 
Since  the  strength  of  the  liquor  used  for  cooking  has  never  been 
standardized,  the  widest  variation  in  this  item  is  found  in  the 
different  mills.  Upon  inquiry,  one  mill  stated  that  they  used 
water  only  as  a  detergent;  another  mill  reported  that  the}^  used 
lime  and  water;  still  another  method  in  practice  is  dependent 
upon  the  action  of  a  soap  solution,  together  with  a  small,  quantity 
of  free  alkali. 

70.  An  accurate  statement  from  data  received  showed  that 
another  mill  was  using  3456  gallons  of  liquor  per  10,000  pounds  of 
paper;  in  this  liquor  was  dissolved  1200  pounds  of  58%  soda  ash 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        41 

and  225  pounds  of  76  %  caustic  soda.  These  alkalis  are  dissolved 
in  two  tanks,  each  7  feet  in  diameter  and  7  feet  deep,  filled  with 
water  to  a  depth  of  6  feet,  the  combined  contents  being  used  for 
one  cook.  These  tanks  are  equipped  with  a  cover  (an  opening 
2|  feet  square  being  allowed  for  the  introduction  of  the  alkalis), 
agitator  arms,  and  a  steam  injection  pipe. 

A  further  report  from  one  of  the  largest  mills  treating  waste 
paper  stated  that  their  consumption  of  soda  ash  amounted  to 
8%  to  9%  of  the  gross  weight  of  the  papers,  as  received  in  the 
sorting  room.  If  an  allowance  of  10%  be  made  for  discards 
on  sorting,  this  consumption  would  be  at  the  rate  of  9  pounds  to 
10  pounds  of  soda  per  100  pounds  of  net  sorted  papers. 

The  lack  of  uniformity  in  the  amounts  of  soda  ash  used  for 
cooking  paper  stock  is  readily  perceived  from  the  figures  stated, 
and  no  attempt  has  been  made  to  standardize  this  figure. 
During  the  last  few  years,  however,  when  the  price  of  soda  ash 
advanced  to  3|  to  5  cents  per  pound,  this  chemical  was  viewed 
with  more  respect,  and  efforts  were  made  to  reduce  its  con- 
sumption. Mills  that  formerly  used  8%  to  10%  are  now  using 
4%  to  5  %.  Should  the  reduction  stop  at  this  latter  figure,  or  is  it 
possible  to  go  still  lower?  Very  careful  experiments  are  being 
conducted  at  one  or  two  mills  to  determine  this  safety  point. 
Cooks  have  been  made  using  3%,  with  no  bad  effects;  but  this 
low  figure  is  not  to  be  considered  as  a  criterion  for  a  standard, 
since  conditions  are  not  always  the  same  at  all  mills.  Too  many 
variables  enter  into  the  problem,  which  must  be  solved  by  each 
individual  mill  to  suit  its  own  equipment  and  conditions.  It 
is  to  be  hoped  that  with  the  adoption  of  standard  cost  methods, 
further  research  will  be  brought  about  in  different  mills,  and  that 
the  results  obtained  will  be  interchanged  more  freely. 

71.  Amount  of  Water  Used. — In  standardizing  rotary  cooking, 
the  volume  of  water  used  should  be  a  known,  constant  figure. 
From  inquiries  made  at  numerous  mills,  only  one  had  in  practice 
a  method  of  measuring  the  water.  Many  mills  stated  that  they 
filled  the  rotary  up  to  a  certain  viark,  or  else  permitted  a  water 
line  to  be  open  for  a  certain  length  of  time.  Here,  at  least,  is  a 
step  that  can  be  taken  in  the  direction  of  a  standard  for  uniform 
operation — the  installation  of  a  water-measuring  tank. 

72.  Rotary  cooking  accomplishes  two  things  at  the  same 
time;  viz.,  de-fibering  and  de-inking.     The  de-inking  has  been 


42  TREATMENT  OF  WASTE  PAPERS  §2 

considered  a  chemical  change,  but  it  may  also  be  classified  as  a 
physical  change.  The  slow  revolving  motion  of  the  rotary 
creates  a  tremendous  amount  of  friction  of  surfaces,  of  attrition 
of  particles  of  paper,  and  the  combined  action  gradually  separates 
the  paper  stock  into  its  component  parts — fiber,  filler,  size, 
and  ink  particles.  AVith  lapse  of  time,  this  action  produces  a 
colloidal  solution,  or  suspension,  of  ink  particles  and  fiber 
particles. 

73.  Increasing  the  Effect  of  Friction. — The  question  naturally 
arises — how  can  the  friction  between  the  inked  surfaces  of  the 
paper  be  increased  ?  Speeding  up  the  number  of  revolutions  per 
minute  of  the  rotary  may  help,  but  onl}^  to  the  point  where  the 
stock  gets  the  greatest  tumbling  action,  and  without  cling- 
ing to  the  shell  on  account  of  the  increased  centrifugal  force. 
Increasing  the  number  of  pins  or  angle  bars  may  help;  but  it 
may  have  an  adverse  effect,  if  the  rotary  speed  be  not  carefully 
worked  out.  The  use  of  too  much  water  will  increase  the  slip- 
page of  the  particles  of  stock  upon  one  another,  allowing  the  stuff 
to  slip  around  without  doing  much  de-fibering.  Likewise,  by 
not  using  sufficient  water,  danger  of  uncooked  papers  may  be 
encountered.  It  would  therefore  appear  that  this  factor  in 
rotary  cooking  is  a  very  important  one;  and  careful  supervision 
as  to  results  obtained  in  using  varying  amounts  of  water  will 
prove  this  statement.  Cooked  stock  that  is  in  a  finely  ground 
state,  with  particles  not  larger  than  a  bean,  and  which  has 
soaked  up  all  the  liquor  possible  to  saturate  it,  with  no  residual 
unabsorbed  or  free  liquor  present,  can  be  said  to  have  had  the 
proper  consistency  of  paper  and  water  during  the  cooking  period. 

74.  Duration  of  Cook. — When  the  liquor  and  papers  have 
been  completely  furnished,  the  manhole  covers  are  bolted  down 
and  securely  fastened.  The  steam  is  turned  on  and  the  rotary 
boiler  is  set  in  motion.  A  recent  improvement  in  the  construc- 
tion of  the  rotaries  provides  for  the  regulation  of  the  amount  and 
frequency  of  the  steam  injections.  An  automatic  valve  is 
attached  to  the  steam  inlet,  which  operates  and  blows  steam 
only  when  the  pipes  are  submerged  in  liquor.  The  advantages 
of  this  arrangement  are  easily  observed  by  the  decrease  in  the 
amount  of  steam  used,  the  more  thorough  cooking  action,  and 
the  elimination  of  the  possibility  of  scorching  the  papers  with 
live  steam. 


§2        COOKING,  DE-INKING  AND  DE-FIBERING       43 

75.  Variation  in  the  time  of  cooking  and  in  the  steam  pressure 
used,  is  another  feature  of  operations  in  different  mills.  The 
data  received  shows  that  the  cooking  time  varies  from  1  to  10 
hours,  and  that  the  steam  pressure  varies  from  10  to  50  pounds, 
One  mill  recommends  cooking  6  hours  under  40  pounds  pressure, 
while  another  mill  cooks  10  hours  under  50  pounds  pressure.  A 
mill  that  makes  a  very  good  grade  of  paper  reports  that  a  mini- 
mum of  7  hours  is  required  for  a  good  cook,  and  that  2  hours 
extra  is  allowed  to  reduce  the  pressure,  blow  off  the  liquor,  and 
dump  out  the  papers.  The  cooking  in  this  case  is  conducted 
under  20  pounds  pressure. 

The  variations  here  noted  are  attributable  to  the  different 
procedures  in  practice.  In  the  practical  application  of  rotary 
cooking,  it  is  generally  conceded  that  there  are  three  distinct 
factors  that  enter  into  the  correct  cooking  of  the  papers.  These 
factors  are:  (1)  Volume  and  strength  of  cooking  liquor  per  100 
pounds  of  paper  to  be  cooked;  (2)  time  allowed  for  cooking,  ex- 
clusive of  time  necessary  for  blowing  off  pressure  and  dumping 
papers ;  (3)  steam  pressure  used  in  cooking. 

These  three  factors  balance  one  another.  If  any  one  of  the 
three  be  varied,  the  other  two  must  be  varied  also,  but  in  the 
reverse  or  opposite  direction,  to  make  the  balance  perfect  again. 
The  data  received  from  the  different  mills  establishes  the  truth 
of  this  observation .  One  combination  shows :  1494  pounds  of  soda 
ash  in  3500  gallons  of  water  per  10,000  pounds  of  papers,  cooked  7 
hours,  at  20  pounds  pressure;  a  second  combination  is:  14,000 
pounds  of  papers,  cooked  10  hours,  at  50  pounds  pressure,  in  a 
weak  solution  of  soda  ash. 

76.  Dumping,  or  Emptying,  the  Boilers. — The  construction 
of  the  rotarj^  boiler  is  so  arranged  that  when  the  boiler  is  revolved 
and  stopped,  with  the  manholes  facing  downwards,  the  cooked 
papers  discharge  from  the  openings,  the  manhole  covers  having 
been  removed.  There  is  sufficient  incline  on  the  inside  of  the 
boiler  to  cause  the  papers  to  be  removed  almost  entirelj'  by 
gravity.  The  few  remaining  papers,  if  any,  are  raked  out  with 
a  long-handled  iron  hook. 

The  papers  are  discharged  below  the  rotaries  into  dumping  or 
draining  pits.  Some  of  these  pits,  or  tanks,  are  equipped  with  a 
perforated  strainer,  which  allows  the  liquor  to  drain  off  into  a 
separate  catch  pan,  to  be  used  over  again,  if  desired,  in  making 
up    the    new    liquor  for  the  next   cook.     The    dumping  pit  is 


44  TREATMENT  OF  WASTE  PAPERS  §2 

equipped  with   two  washout  valves,  one   draining  valve,  and 
one  large  outlet,  for  the  removal  of  stock  to  the  washers. 

77.  Recovery  of  Liquor. — The  recovery  of  the  soda-ash  liquor 
used  in  rotary  boilers  is  apparently  lost  sight  of;  but,  inasmuch 
as  the  papers  absorb  most  of  the  liquor,  there  is  only  a  relatively 
small  volume  that  freely  drains  off  into  the  dumping  pits.  The 
papers  treated  in  a  rotary  are  reduced  to  a  pulpy  consistency, 
due  to  the  continued  rubbing  and  grinding  action.  The  pulpy 
mass  acts  like  a  sponge,  and  will  absorb  and  hold,  by  capillary 
attraction,  a  large  volume  of  water;  consequently,  unless  it  is 
allowed  to  drain  for  a  considerable  period,  the  recovered  liquor 
will  be  a  small  item. 

The  data  collected  on  the  recovery  of  the  liquor  gave  results 
that  varied  from  11%  to  50%,  the  general  average  being  about 
30%.  One  mill  reported  that  they  did  not  expect  to  recover 
any  of  the  cooking  hquor;  it  was  worthless,  in  their  opinion, 
and  would  merely  discolor  any  fresh  liquor  that  was  made  for  new 
cooks.  A  second  mill  reported  the  average  to  be  approximately 
15%;  and  a  third  mill  observed  that  the  average  was,  roughly, 
33%,  or  one-third  of  the  liquor  used. 

78.  A  very  enterprising  mill  stated  that  they  had  been  thinking 
about  this  loss  of  soda  ash  for  a  number  of  years,  but  had  done 
nothing  definite  to  prevent  it.  They  employed  a  chemist,  who 
advised  them  further  concerning  the  value  of  this  waste,  and  they 
immediately  took  steps  to  provide  a  suitable  drainer  and  catch 
pan  for  the  liquor.  In  the  dumping  pits,  the  cooked  papers 
are  now  subjected  to  a  wash  of  warm  water  after  as  much  as  is 
possible  of  the  cooking  liquor  has  drained  away.  When  the  first 
wash  water  has  drained  off,  a  second  wash  water  is  applied;  in 
this  manner,  the  recovery  was  increased  to  60%.  Such  efforts 
will  pay,  no  doubt,  when  8%  to  10%  of  soda  ash  is  used,  and  when 
the  price  of  soda  ash  is  high;  but  it  is  a  very  debatable  question 
when  only  3%  of  soda  ash  is  used,  as  is  now  frequently  the  case. 
The  cost  entailed  in  saving  the  waste  may  be  greater  than  the 
cost  of  the  chemicals  saved. 

79.  Spherical  Boilers. — This  type  of  cooker  is  operated  in  the 
same  manner  as  the  cylindrical  type.  An  illustration  of  a 
spherical,  or  globe,  boiler  is  given  in  Section  1  of  this  volume. 

80.  Power  Required. — The  manufacturers  recommend  the  use 
of  8  h.p.  for  an  8  ft.  X  24  ft.  boiler;  but  actual  practice  has  shown 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        45 

that  4^  h.p.  is  sufficient.  One  installation  of  this  size  of  rotary- 
calls  for  a  5  h.p.  motor  for  each  rotary,  and  the  motor  is  seldom 
called  on  to  approach  its  rating.  The  boiler  revolves  so  slowly, 
about  1  revolution  every  2  or  2j  minutes,  that  the  driving  power 
required  is  small. 

81.  Furnishing  Cooked  Papers  to  Washers. — After  the  cooking 
liquor  has  drained  off  as  much  as  possible,  the  papers  are  ready 
to  be  furnished  to  the  washers,  and  this  is  effected  in  one  mill  by  a 
very  ingenious  arrangement.  It  was  previously  stated  that  it 
required  the  combined  efforts  of  six  men  to  move  the  loaded  cars 
of  cooked  papers  to  the  washers  when  the  open-tank  method  of 
cooking  was  used.  In  the  mill  here  referred  to,  in  which  rotaries 
are  used,  the  dumping  pit  is  equipped  with  a  dumping  valve  that 
leads  into  a  vertical  cylinder,  about  3  feet  deep  and  2  feet  in  diam- 
eter, placed  directly  under  the  dumping  pit  and  equipped  with 
agitator  propellor  arms  that  are  driven  from  a  separate  motor. 
The  pulpy,  cooked  papers  flow  toward  this  cylinder,  and  they  are 
hastened  along  by  a  water-pressure  hose  line.  In  the  cylinder, 
they  are  agitated,  to  prevent  any  clogging  of  the  pipe  line  through 
which  the  papers  are  pumped  direct  to  the  washers.  This 
procedure  effects  a  great  saving  in  time,  in  labor,  and  in  cleanli- 
ness of  the  cooking  and  washing  rooms. 

Fig.  12(c)  shows  a  cross  section  of  an  agitator  device  A  now  in 
quite  common  use  in  the  more  modern  mills;  it  is  a  very  simple 
arrangement,  and  is  entirely  satisfactory  in  operation.  A  careful 
examination  of  the  drawdng  is  a  sufficient  explanation  of  the 
construction. 

82.  Remarks  Concerning  the  Rotary  Process. — The  rotary 
process  for  cooking  old-paper  stock,  and  the  dependent  methods 
of  handling  the  cooked  papers,  is  regarded  as  the  most  convenient, 
the  most  efficient,  and  the  most  practical  method  in  use.  This 
view  is  held,  in  particular,  by  those  mills  that  have  rotaries  in 
use  or  which  expect  to  install  them.  While  initial  cost  is  con- 
siderable, the  absence  of  steam  and  condensation  and  of  the 
accumulation  of  papers  and  alkali  liquors,  the  lessening  of  depre- 
ciation throughout  the  entire  process,  and  the  decrease  in  the 
labor  cost  attending  the  cooking  and  washing  processes,  are 
considered  to  be  factors  that  more  than  counterbalance  the  extra 
first  cost  of  installation.  The  entire  process  is  more  healthful 
to  the  workmen,  and  the  cleanliness  throughout  appeals  to  all 


46 


TREATMENT  OF  WASTE  PAPERS 


§2 


who  are  familiar  with  other  methods  of  treating  waste  papers. 
Some  recent  developments,  however,  have  features  which  are 
strong  arguments  for  the  newer  processes. 


QUESTIONS 

(1)  State  the  advantages  of  a  rotary  boiler  and  explain  the  method  of 
furnishing  it. 

(2)  How  much  soda  ash  is  commonly  used  per  100  lb.  of  paper  cooked? 

(3)  Why  is  the  amount  of  solution  used  so  important? 

(4)  How  does  the  rotary  help  to  de-ink  waste  paper? 

(5)  What  is  the  next  step  after  the  cooking  is  complete? 


COOKING-ENGINE  PROCESS 


83.  Description  of  Cooking  Engine. — The  cooking  engine  for 

waste  papers  is  a  machine  of  the  type  shown  at  A,  Fig.  13;  it  is 
essentially  a  variation  of  the    beater  or  washer    described  in 


[o)^r^^^ 


Fig.  13. 

Sections  1  and  3  of  this  volume.  An  elliptical-shaped  tub,  about 
8  ft.  X  20  ft.  and  3  feet  deep,  is  divided  down  the  center  b}-  a  mid- 
feather,  and  in  one  side  of  the  channel  is  a  beater  roll  or  propeller. 
The  tub  is  covered  as  tightly  as  possible  with  steel  plate,  the 
end  covers  being  hinged  and  held  dow'n  by  bolts  or  clamps. 

Waste  papers  are  prepared^  as  previously  described;  the}'  are 
stored  on  the  floor  above  or  in  bins,  and  are  furnished  by  a  chute  B, 
Fig.  13.     The  cooking  liquor,  usually  a  dilute  solution  of  soda  ash, 

1  In  Fig.  13,  Cr  is  a  bale  of  papers,  H  a  belt  conveyor,  K  a  railroad  duster, 
L  a  sorting  conveyor,  M  a  fan  duster,  N  an  inclined  conveyor,  P  a  pile  of 
prepared  stock. 


§2        COOKING,  DE-INKING  AND  DE-FIBERING       47 

is  run  into  the  engine  A  until  the  alkali  content  is  equivalent  to 
10%  of  the  weight  of  the  papers  that  the  engine  can  handle.  This 
amount  will  fill  the  tub  to  a  certain  depth,  say  half  full.  The 
papers  are  then  furnished  and  are  circulated  by  the  roll  or  paddle, 
and  they  are  soaked  with  the  liquor  at  the  same  time.  Water  is 
added  as  necessarj^,  and  more  papers  are  fed  in  until  the  desired 
consistency,  about  6%,  is  reached.  A  charge  is  about  1200  lb. 
of  papers.  While  the  charge  is  being  furnished  and  washed,  the 
contents  are  heated  bj-  steam,  at  full  boiler  pressure,  for  about 
1^  hours.  The  agitation  created  during  circulation  de-fibers  the 
paper  and  assists  the  chemical  action  of  the  liquor  in  loosening 
the  ink  particles,,  which  are  removed  in  the  subsequent  washing. 
The  cooking  time  is  about  2  hours,  varjdng  somewhat  with  the 
grade  of  the  waste  papers ;  old  ledger  and  the  like  require  a  longer 
time  to  disintegrate.  The  power  required  is  used  almost  entirely 
for  circulation,  and  will  average  25  to  30  h.p. 

84.  When  the  papers  are  thoroughly  cooked  and  re-pulped,  a 
valve  is  opened,  and  the  pulped  papers  are  allowed  to  flow  into 
chests  C,  Fig.  13.  No  attempt  is  made  to  recover  any  of 
the  cooking  liquor,  as  it  is  considered  not  to  have  any  value.  The 
papers  are  furnished  to  the  washers  D  by  pumping  from  the 
chests  C  into  which  the  papers  were  dumped  after  being  cooked. 
After  washing,  the  stock  goes  to  chest  E,  from  whence  it  is 
pumped  to  the  beaters  F. 

85.  Advantages  of  the  Process. — The  cooking  engine  process 
is  claimed  to  have  the  following  advantages:  (1)  Dusted  papers 
are  furnished  from  storage  direct  to  engines;  this  provides  for  a 
storage  always  on  hand,  and  it  calls  for  a  minimum  of  labor  for 
furnishing.  (2)  Engines  are  covered  tightly ;  this  saves  in  steam 
and  heat.  (3)  Papers  are  re-pulped  better  than  in  the  old  type 
of  rotaries;  this  lessens  the  amount  of  work  required  later  for 
beating  and  brushing  out  in  washers  and  beaters.  (4)  Papers 
are  thoroughly  soaked  in  the  cooking  liquor;  there  is  here  no 
possibilit}^  of  a  dry  cook.  (5)  Papers  are  handled  by  gravity, 
both  before  and  after  being  cooked;  this  eliminates  the  hand 
labor — a  costly  item  in  the  open-tank  process.  (6)  Small  labor 
cost  throughout. 

What  may  be  called  disadvantages  or  costly  features  are:  (1) 
No  recovery  of  the  cooking  liquor;  this  results  in  a  large  con- 
sumption of  soda  ash.     (2)  A  large  amount  of  steam  is  used;  full 


48 


TREATMENT  OF  WASTE  PAPERS 


boiler  pressure  is  maintained  for  1^  hours.  (3)  Large  expen- 
diture of  power  is  required  to  circulate  the  papers.  (4)  The  oil 
consumption  and  belting  wear  and  tear  is  large;  extra  with  belt- 
driven  pulleys.  (5)  General  wear  and  tear  and  depreciation  are 
greater.  (6)  The  pulp  product  is  considered  to  be  weaker ;  caused 
by  the  violent  action  of  the  steam,  alkali,  and  the  brushing  action 
on  the  pulp.  (7)  Poor  color  of  recovered  pulp,  compared  with 
open-tank  pulp,  and  not  as  good  as  rotary  pulp. 


A  SEMI-MECHANICAL  PROCESS 

86.  Treating  Old -paper  Stock  Mechanically. — A  new  (patented) 
method  has  recently  been  perfected;  it  is  in  use  in  a  few  places, 
but  has  not  as  yet  been  completely  adopted  in  the  older  mills. 
This  method  is  largely  mechanical  in  its  action,  and  the  details 
are  illustrated  in  Figs.  14  and  15.  The  advent  of  this  machine  gave 
a  wonderful  impetus  to  the  idea  of  treating  paper  stock  mechanic- 
ally. There  is  now  quite  a  varied  line  of  processes  that  might  be 
thought  to  have  originated  from  the  idea  of  propeller  de-fibering; 
these  will  be  considered  later. 

87.  Description  of  the  Process.— This  process  was  first  brought 
to  the  attention  of  the  general  public  in  1914-1915.     Fig.  14 

illustrates  the  design  of  the 
machine,  which  consists  of  an 
inner  cylindrical  tank  A  that 
leads,  at  its  bottom,  into  a 
draft  tube  B,  through  which 
extends  lengthwise  a  shaft  F, 
to  which  are  fixed  two  pro- 
pellers C  and  Ci,  spaced  apart 
from  each  other,  and  of  differ- 
ent pitch.  The  propellers, 
which  are  rotated  at  about 
2000  r.p.m.,  draw  the  material 
downwards  from  tank  A ,  drive  it  through  tube  B,  and  up  through 
the  course  D  at  high  velocity,  estimated  at  1200  ft.  per  min. 

The  course  D  discharges  at  a  tangent  into  an  outer  chamber  H, 
which  surrounds  the  chamber  A  and  is  concentric  with  it.  The 
material  entering  chamber  //  at  a  tangent  circulates  and  rises 
spirally  therein,  as  indicated  by  the  arrows;  it  then  cascades  over 


Fig.  14. 


§2        COOKING,  DE-INKING  AND  DE-FIBERING       49 

the  upper  edge  of  chamber  A,  and  repeats  its  course  of  circulation 
through  draft  tube  B,  propellers  C  and  Ci,  and  chamber  //.  The 
machine  maintains  a  perfect  circulation  until  all  the  stock  is 
de-fibered.  The  stock  is  withdrawn  from  the  apparatus  through 
suitable  pipes  G,  which  lead  from  the  mid  length  of  the  tube  B  and 
from  the  bottom  of  chamber  H,  as  shown.  During  the  feeding  of 
the  machine,  water  is  supplied  through  pipe  E,  and  steam  for 
heating  is  admitted  at  intervals,  as  needed,  through  pipe  J, 
shown  below  the  course  D. 

The  de-fibering  action  is  due  to  the  propellers  C  and  Ci,  which 
revolve  so  rapidly  that  the  water  is  unable  to  take  up  the  rotary 
speed  thereof.  Consequently,  there  are  two  opposing  forces,  one 
being  caused  by  the  speed  of  the  propeller  and  the  other  by  the 
inertia  of  the  liquid  and  stock.  In  addition  to  these  two 
de-fibering  forces,  there  is  another  action,  which  may  be  described 
as  the  constructive  and  explosive  effect  on  the  fibers  that  is 
caused  by  the  difference  in  the  pitch  of  the  two  propellers  C 
and  Ci.  The  blades  of  propeller  C  have  a  greater  pitch  than 
those  of  propeller  Ci,  which  creates  a  tendency  to  form  a  vacuum 
between  the  two  propellers,  thus  producing  what  is  described 
as  an  explosive  or  disintegrating  effect  on  the  stock. 

88.  De -inking  Action. — As  to  the  de-inking  action,  it  appears 
that  when  wet  paper  that  has  been  printed  with  ordinary  black 
printers'  ink  is  torn,  any  ink  that  is  on  the  line  of  tear  is  much 
loosened  by  the  pulling  apart  of  the  paper  fibers;  so  much  so,  in 
fact,  that  the  adhesion  of  such  portions  of  the  ink  as  remain  on  the 
fringes  of  disengaged  fibers  at  the  torn  edges  is  much  less  than  the 
normal  adhesion  of  ink  to  untorn  paper.  This  is  probably  due 
to  the  fact  that  the  dry  black  ink  is,  physically,  a  species  of  film 
or  incrustation,  which  sticks  to  the  paper  by  reason  of  the 
adhesive  properties  of  the  ink,  but  which  is  capable  of  being 
mechanically  loosened  by  the  relative  motions  of  the  wet  matted 
fibers  to  which  it  is  stuck.  Now  if  the  paper  be  torn  into  such 
fine  bits  that  the  paper  fiber  foundation  to  which  each  particle  of 
ink  adheres,  is  wholly  or  partly  pulled  apart, — that  is,  if  the 
paper  is  completely  pulped  or  de-felted, — then  this  loosening 
action  affects  all  the  ink  and  renders  it  easy  to  remove. 

89.  Character  of  Paper  Produced. — Obviously,  some  types  and 
grades  of  paper  stock  can  be  reduced  to  a  pulp  more  readily 
and  with  less  deterioration  than  others.     A  pulp  made  from  a  free 


50  TREATMENT  OF  WASTE  PAPERS  §2 

stock,  in  which  the  fibers  in  the  original  paper  making  were  not 
greatly  hydrated,  is,  of  course,  felted  together  rather  than  stuck 
together,  and  it  is  much  more  amenable  to  a  disintegrating  or 
de-felting  action  than  a  paper  made  of  over-beaten  or  slow  stock, 
in  which  the  fibers  are  so  much  hj'^drated  and  glutinous  that  they 
are  more  or  less  welded  together  as  well  as  felted.  Extreme 
examples  of  such  papers  are  pergamyn  or  glassine  papers. 

90.  Method  of  Cooking. — The  following  statement  was 
obtained  from  a  superintendent  who  had  one  of  these  machines 
under  his  direct  care  and  supervision: 

"We  are  at  present  cooking  with  5%  soda  ash,  using  about 
900  pounds  of  stock  to  a  batch,  and  we  take  about  50  minutes  to 
a  batch,  the  density  of  which  is  around  5  %.  While  one  batch  is  in 
process,  we  are  softening  another  in  the  tank  above,  using  the 
exhaust  steam  from  the  turbine  for  heating.  We  raise  the  tem- 
perature to  160°-180°F.,  never  guessing  at  it,  but  always  using  a 
thermometer,  as  we  get  the  best  results  in  this  way." 

91.  Cost  of  Operation. — This  superintendent  further  states: 
"As  to  the  cost  of  operation,  this  is,  indeed,  a  hard  matter  to 
determine.  There  is,  of  course,  a  saving  of  about  3%  in  soda 
ash,  as  well  as  the  saving  of  time  in  washing,  which  may  counter- 
balance to  some  extent  the  extra  power  consumption.  There  is 
also  a  big  difference  in  the  cost  of  handling,  which  is  quite  an  item 
in  the  vomiting  process;  in  fact,  I  may  venture  to  state  that  this 
item  was  responsible  for  the  advent  of  the  rotary.  There  is  also 
to  be  considered  the  matter  of  the  elimination  of  the  dirty  mess 
caused  by  the  dripping  of  the  alkali  from  the  boxes,  and  the 
condensation  caused  during  the  cooking  process." 

It  may  be  remarked  that  a  75-h.p.  turbine  has  been  specified 
for  the  satisfactory  operation  of  the  process. 

92.  Advantages  and  Disadvantages.— The  chief  objection  to 
this  process,  which  was  later  raised  at  the  above  mentioned  mill, 
was  its  consumption  of  steam  for  power  and  heating.  Even 
though  the  stock  traveled  1200  ft.  per  min.  in  this  machine,  it  was 
found  that  dead  pockets  of  stock  remained  in  the  machine  and 
were  not  acted  upon,  which  resulted  in  dirty  paper  stock;  this 
happened  from  oversight  or  carelessness  in  not  getting  the  proper 
density  (that  is,  the  correct  proportion  of  weight  of  papers  and 
volume  of  water)  in  the  tank.  If  the  charge  were  too  heavy  on 
entering  the  machine,  only  that  portion  around  the  central  tube 


§2        COOKING,  DE-INKING  AND  DE-FIBER  ING        51 

circulated  freely.  It  has  been  suggested  that  the  chamber  H  be 
divided  by  a  helical  passage,  so  arranged  that  the  stock  will 
circulate  around  and  around  the  central  tube  until  it  finally  comes 
to  the  top  and  splashes  over  into  the  central  tube  again,  to  begin 
its  journey  once  more.  If  given  proper  attention  by  men  who 
can  regulate  the  stock  to  a  uniform  consistency,  this  machine 
will  produce  a  product  that  can  be  readily  washed,  screened,  and 
made  into  good  paper.  The  color  is  a  blue  white,  though  not  any 
bluer  than  stock  produced  by  any  other  mechanical  process, 
such  as  the  rotary  boiler  or  any  of  the  later  centrifugal-pump  and 
tank  systems. 

93.  The  amount  of  steam  consumed  is  that  required  to  raise 
the  temperature  of  the  water  in  the  de-fibering  machine  to  160°F., 
and  for  no  other  purpose ;  this  represents  approximately  300,000 
B.t.u.  per  100  pounds  of  paper. 

94.  Layout,  and  Sequence  of  Operations. — With  the  exception 
that  no  provision  for  bleaching  need  be  made,  and  that  the  boiler 
capacity  may  be  limited  to  that  required  for  any  new  furnish  and 
for  mixing  the  recovered  stock  with  this  new  furnish,  the  process 
just  described  uses  substantially  the  same  auxiliary  apparatus 
as  would  be  used  in  any  other  process  that  employs  a  mechanical 
pulper.  The  sequence  of  operations  is  as  follows:  According  to 
their  condition,  the  papers  are  first  sorted  by  hand  or  are  dusted 
in  a  duster  and  afterwards  sorted;  the  first  procedure  is  used 
when  the  papers  are  reasonably  clean.  The  papers  are  then 
torn  and  are  again  dusted  in  a  railroad  duster  or  its  equivalent. 
The  torn  papers  are  next  conveyed  upwards  by  a  belt,  apron,  or 
an  air  conveyor  to  a  soaking  tank  having  an  agitator,  in  which 
they  are  thoroughly  wet  in  water  at  about  160°F.  This  tank  A, 
Fig.  15,  is  so  placed  that  it  can  quickly  charge  the  de-fibering 
machine,  which  works  in  batches.  The  water  in  tank  A  is 
preferably  heated  by  the  exhaust  from  a  steam  turbine  that 
drives  the  machine. 

The  de-fibering  machine  B,  Fig.  15,  is  the  next  element  in  the 
layout,  and  its  general  principle  has  been  already  sufficiently 
described.  Quick-opening  valves  must  be  provided  for  rapid 
charging  and  discharging;  the  time  required  for  these  operations 
being,  even  under  the  most  favorable  conditions,  a  considerable 
proportion  of  the  total  time  of  operation.  The  pulp  from  the 
machine  passes  to  the  de-inked  stock  chest  C;  it  requires  washing 


52 


TREATMENT  OF  WASTE  PAPERS 


§2 


only,  or,  at  the  most,  washing  and  brushing  out  in  the  Jordan,  to 
render  it  suitable  for  delivery  to  the  stuff  chest.  The  washing 
arrangements,  indicated  at  D,  are  of  the  utmost  importance  for 
removing  the  loosened  ink.  The  washing  layout  differs  more  or 
less  in  details,  according  to  local  conditions;  but  with  an  arrange- 
ment of  ordinary  efficiency,  the  pulp  should  be  washed  for  about  2 
hours.  The  pulp  from  the  final  tank  will  be  of  3%  to  5% 
consistency;  it  can  usually  be  pumped  to  the  paper-machine  chest, 
if  unmixed  recovered  stock  is  to  be  employed ;  or  it  may  be  pumped 
to  the  beater  or  other  receptacle,  in  which  it  may  be  mixed  with 


Fig.  15. 

any  new  stock  that  is  to  be  added.  In  some  cases,  it  may  be 
desirable  to  brush  out  the  recovered  stock  in  the  Jordan  before 
sending  it  to  the  stuff  chest;  the  piping  arrangements  should  be 
such  that  this  can  be  done,  or  the  Jordan  should  be  by-passed, 
as  conditions  indicate. 

Where  magazine  stock  is  treated,  and  sometimes  in  other  cases 
also,  it  is  advisable  to  pass  the  stock  from  the  de-inked  stock 
chest  through  a  wire  catcher,  on  the  way  to  the  washer.  The 
washer  may  be  an  ordinary  flat  screen,  or  a  long  channel  with 
dams,  or  a  deep  well.  The  well  is  made  about  2  feet  square  and 
25  feet  deep,  with  a  partition  in  the  middle  that  reaches  nearly 
to  the  bottom.     The  stock,  diluted  to  about  1  %  consistency,  is 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        53 

fed  at  the  top  of  one  side,  passes  down,  drops  the  pins,  and  is 
dcHvered  near  the  top  again. 

95.  Pulping  Engine. — A  pulping  engine,  which  may  be  used  in 
place  of  tank  A,  Fig.  15,  in  connection  with  the  de-fibering  machine 
just  described,  is  shown  in  Fig.  16.  This  consists  of  an  eUiptical- 
shaped    tub    A,  with    midfeather  B,  in  which  the  mixture  of 


Fig.  16. 

shredded  papers  and  cooking  liquor  is  circulated  by  a  paddle 
wheel  W,  which  makes  about  19  r.p.m.  The  shaft  T,  which  turns 
at  150  r.p.m.,  is  studded  with  wooden  slats  *S,  which  slash  the  paper 
into  fragments  and  mix  them  with  the  liquor.  One  of  these 
engines  will  hold  1700  pounds  of  paper,  dry  weight. 


NEW  TANK  AND  PUMPING  SYSTEM 

96.  Remark. — During  the  World  War,  manufacturing  methods 
and  processes  were  given  closer  scrutiny  than  at  any  previous 
time.     Work  that  required  manual  labor,  and  which  had  received 


54 


TREATMENT  OF  WASTE  PAPERS 


§2 


scant  attention  up  to  that  time,  possibly  because  of  the  abund- 
ance of  willing  workers  at  low  wages,  was  supplanted  by 
machinery  and  mechanical  processes.  It  is  therefore  not  strange 
that  this  change  also  occurred  in  the  processes  for  the  conversion 
of  old-paper  stock.  After  the  introduction  of  the  de-fibering 
process  just  described,  many  applications  were  made  of  the  idea 
of  de-inking  and  de-fibering  paper  stock  by  propelling  and  circu- 
lating with  centrifugal  pumps,  and  by  impinging  the  stock  and 
water  against  a  plane  surface,  a  conical  surface,  a  Y  or  T  surface, 
or  even  against  itself,  in  divided  streams. 

97.  Improved  Cooking  System. — One  very  enterprising  mill 
that  formerly  used  the  open-tank  system  has  installed  a  new 
system,  which  not  only  saves  50%  of  the  building  space,  a  very 


Fig.  17. 


important  item  in  costs,  but  also  effects  a  saving  of  50%  in 
soda  ash,  and  saves  the  services  of  28  men  and  30  women.  This 
change  was  effected  by  using  the  old  tanks  in  the  new  construc- 
tion, by  installation  of  the  carrier  system  of  sorting,  and  by  com- 
bining what  was  formerly  two  sorting  rooms  and  two  cooking 
rooms  into  one  sorting  room  and  one  cooking  room. 

Fig.  17  represents  one  of  four  similar  cooking  tanks,  each  10 
feet  in  diameter  and  26  feet  in  length,  suitably  mounted  on  concrete 
piers.  Each  tank  is  equipped  with  a  specially  designed  agitator, 
having  arms  S,  which  are  staggered  on  the  central  shaft  and  are 
so  arranged  that  complete  agitation  is  assured  at  a  speed  of  10 
r.p.m.  The  agitator  is  belt  driven,  and  the  power  is  furnished 
by  individual  10-h.p.  motors;  the  motor  and  the  agitator  drive 
are  shown  at  C  and  D.     Although  10-h.p.  motors  are  used,  actual 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        55 

tests  indicate  that  3.5  to  5-h.p,  is  sufficient;  but  for  safe  working, 
it  was  deemed  advisable  to  have  a  motor  of  sufficient  power  to 
take  care  of  anj^  unusual  condition  that  might  develop,  as  when 
more  than  7500  pounds  of  paper  stock  is  cooked  and  agitated  at 
an  increased  density. 

98.  Method  of  Operation. — The  paper  stock,  which  has  been 
previously  dusted  and  shredded  into  pieces  2  inches  square,  is  blown 
through  an  18-inch  diameter  air  duct  from  the  sorting  room  into 
the  charging  manhole,  shown  at  M,  Fig.  17.  To  allow  the  escape 
of  air  during  the  charging,  a  vent  N  is  provided  at  the  other  end 
of  the  tank.  A  6-inch  water  pipe  W  supplies  water  to  each  tank 
while  6500  to  7500  pounds  of  stock  is  being  introduced.  Soda  ash 
to  the  amount  of  4%,  based  on  the  dry  weight  of  the  paper  stock 
charge,  is  dissolved  in  the  soda-ash  tank,  which  is  located  where 
convenient,  but  preferably  on  the  floor  above  the  cookers.  The 
filling  operation  takes  from  20  to  30  minutes.  The  temperature 
of  cooking  is  maintained  at  200°F.,  so  that  the  consumption  of 
steam  is  not  so  great  as  in  the  open-tank  or  rotarj'-boiler  processes. 
The  steam  inlets  are  shown  at  H,  Hi,  H2,  and  Hz]  thej''  are  made 
of  f-inch  piping,  reduced  from  a  l^-inch  line,  on  which  the  valve 
is  located.  When  properly  filled  with  paper  and  water,  the  stock 
should  have  a  consistency  of  8%. 

99.  De-fibering  and  De-inking. — The  de-fibering  and  de- 
inking  of  the  stock  are  effected  by  an  8-inch  centrifugal  pump  P, 
direct-connected  to  a  40-h.p.  motor  T.  The  pump  is  especially 
designed  for  this  work;  it  has  impellers  of  sufficient  rigidity,  and 
is  constructed  to  de-fiber  and  circulate,  without  plugging,  at  a 
speed  of  1700  r.p.m.  Under  the  heaviest  loads,  36  h.p.  is 
required  to  operate  the  pump,  but  the  average  for  30  daj's  was 
only  18  h.p.  However,  when  it  is  necessary  for  the  pump  to 
take  up  peak  loads,  such  as  an  extra  heavy  wad  or  slug  of  stock, 
the  extra  power  then  needed  is  available. 

100.  The  circulation  of  the  stock  is  effected  by  means  of  3 
8-inch  pipe  lines  F,  which  lead  to  the  pump  inlet,  and  by  2 
8-inch  pipe  lines  G,  which  lead  from  the  pump  discharge  back  to  the 
cooking  tank.  The  pipes  G  conduct  back  to  the  top  of  the  tank 
the  stock  that  impinges  on  the  T  connection,  shown  at  X,  where 
further  de-fibering  takes  place.  The  T  connection  is  considered 
to  hasten  the  preparation  of  the  stock,  because  of  the  friction 


56  TREATMENT  OF  WASTE  PAPERS  §2 

and  the  churning  that  the  mixture  of  paper  and  water  receives 
at  this  point. 

After  circulating,  de-fibering  and  cooking  for  one  hour  at  a 
temperature  of  200°F.,  the  papers  are  considered  to  be  cooked. 
By  opening  valve  V2  or  V3  and  closing  Vi,  the  cooked  stock  is 
conducted  by  lines  X  or  L  to  storage  tanks,  not  shown  in  the 
figure.  From  20  to  30  minutes  is  required  to  empty  the  cooking 
tank.  The  process  consumes  30  minutes  for  filling,  60  minutes  for 
cooking,  and  30  minutes  for  dumping,  a  total  of  2  hours,  for  6500 
to  7500  pounds  of  de-fibered  stock.  This  compares  very  favorably 
with  5  to  10  hours  for  cooking  5000  to  6000  pounds  of  papers  in 
the  open-tank  process. 

101.  Fewer  Employes  than  with  Open-Tank  System. — A 
comparison  of  the  labor  employed  with  the  improved  system 
with  that  employed  with  the  open-tank  system  shows  that  the 
improved  system  will  do  the  combined  work  of  two  sorting  rooms 
used  with  the  open-tank  process.  Specifically,  the  old  system 
requires  2  rooms  for  sorting  on  the  bench  method;  2  foremen; 
6  carrier  men,  for  emptying  barrels  onto  conveyors;  4  truckers, 
for  trucking  barrels  of  sorted  papers  from  benches  to  conveyors; 
6  cook-room  men,  2  to  make  soda  ash  and  4  to  fill  open  tanks 
with  papers;  4  unloader  men,  to  remove  cooked  stock  from  tanks 
with  pitchforks;  2  washer  rooms,  with  4  men  in  each  room; 
24  washer  men,  8  men  on  each  tour,  to  fill  washers  by  forking 
stock  from  small  cars;  60  sorting  girls.  This  shows  a  total  of  54 
men  and  60  women. 

The  improved  system  requires  only  one  (1)  room  for  sorting 
60  tons  of  paper;  the  conveyor  system  replaces  the  bench  method 
of  handling  the  papers;  and  there  is  required:  1  foreman;  3 
floormen,  to  truck,  lay  down,  and  open  bales  at  the  conveyors; 
2  cook-room  men,  1  to  make  soda  ash  and  regulate  steam  and 
water,  and  1  to  fill  and  discharge  cookers  and  to  pump  stock;  12 
washer  men,  4  men  on  tour  in  2  rooms  (2  men  for  each  tour); 
30  sorting  girls.  This  shows  a  total  of  18  men  and  30  women, 
which  is  a  reduction  of  36  men  and  30  women  as  compared  with 
the  open-tank  system.  A  saving  of  two-thirds  the  number  of 
men  and  one-half  the  number  of  women  formerly  required  to 
produce  the  same  tonnage,  is  a  marked  step  forward  in  lowering 
manufacturing  costs.  The  improved  S3'stem  is  a  distinct  credit 
to  the  mill  employing  it,  and  unstinted  praise  is  due  to  the 
superintendent  who  planned  and  worked  out  the  process. 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        57 

USE  OF  WASTE  PAPERS  FOR  MAKING  BOARDS 

102.  Use  of  Discards. — There  is  much  waste  paper  collectcHl 
that  cannot  be  made  into  white  paper;  to  this  must  be  added  the 
discards  from  the  sorting  processes  previously  described.  Still, 
even  this  low-grade  material  is  graded  for  special  uses;  it  is  highly 
valued  for  test  board  and  wrapping  paper  and  in  the  manufacture 
of  kraft  paper.  Other  grades  of  discards,  including  old  box 
boards,  etc.,  go  into  pasteboards,  card  middles  -and  similar 
papers.  Less  care  is  required  in  sorting  discards,  and  they  are 
very  often  furnished  direct  to  the  beaters. 


QUESTIONS 

(1)  Describe  the  cooking  engine. 

(2)  Would  you  consider  it  worth  while  to  recover  the  chemical  used  in 
cooking  by  the  process  described  in  Art.  87?     Give  reasons  for  your  reply. 

(3)  Upon  what  principle  does  the  mechanical  de-inking  of  paper  by  the 
process  of  Art.  87  depend? 

(4)  If  5  %  of  soda  ash  is  required  for  a  batch  of  900  lb.  of  papers,  what  is 
the  weight  of  soda  ash  required?  Ans.  45  lb. 

(5)  How  is  the  de-fibering  and  de-inking  of  stock  effected  by  the  process 
described  in  Arts.  99  and  100? 

(6)  Referring  to  Fig.  17,  explain  briefly  the  operation  of  the  apparatus 
there  illustrated. 

(7)  Mention  some  of  the  advantages  that  the  improved  system  has  as 
compared  with  the  open-tank  system. 


TREATMENT  OF  COOKED  PAPER  STOCK 


WASHING  THE  STOCK 

103.  The  Third  Step. — The  third  very  important  step  in  the 
treatment  of  waste  papers  pertains  to  the  washing  and  the 
subsequent  bleaching  of  the  cooked  paper  stock. 

104.  Washing  Engine. — Many  different  methods  are  used  in 
washing  the  papers,  the  most  general  process  being  that  in  which 
washing  engines  are  used.  These  engines,  fully  described  in 
Section  1,  consist  of  a  beater-shaped  tub,  a  circulating  roll  that 
is  equipped  with  blunt  steel  knives,  but  without  a  bed  plate,  and 
2  to  4  octagonal-dnmi  washing  cylinders  (see  Figs.  1 1  and  12, 
Section  1), 


58  TREATMENT  OF  WASTE  PAPERS  §2 

The  capacity  of  this  type  of  beater  is  from  800  pounds  to  2000 
pounds,  the  average  being  about  1600  pounds.  The  circulating  roll 
is  raised  or  lowered  by  means  of  a  worm  gear,  in  order  to  varj^  the 
slight  brushing  action  that  the  stock  receives.  By  installing  a  bed 
plate  and  using  sharper  knives,  these  washers  can  be  readily 
converted  into  beating  engines.  The  octagonal-drum  washing 
cylinders  are  constructed  on  the  usual  bucket  arrangement 
pattern.  The  faces  of  the  cylinders  are  first  covered  with  j-inch 
mesh  facing  wire,  and  are  topped  with  60-  or  70-mesh  washer 
wire.  It  has  been  the  custom  heretofore  only  to  use  old  Four- 
drinier  machine  wire  for  facing  the  cylinder;  but  experiment  has 
proved  that  a  larger  screening  surface  is  obtained  by  using  the 
larger  |-inch  mesh  wire  for  facing  and  covering  this  with  wire 
that  has  been  woven  especially  for  the  washing  of  stock.  Nickel- 
alloy  60-mesh  wires  have  been  placed  on  the  washing  drums;  and, 
after  1^  years  of  service,  they  have  shown  no  perceptible  wear. 
They  do  not  require  any  scouring  out  with  acid,  and,  barring 
accident  from  puncture,  they  should  have  a  much  longer  life 
than  this.  The  cylinders  are  equipped  with  a  raising  and 
lowering  ratchet  wheel. 

105.  Operations. — After  being  thoroughly  cooked,  the  papers 
are  furnished  to  the  washers,  either  from  the  chest  C,  Fig.  15,  or 
as  described  in  Art.  81.  Sometimes  2  or  3  quarts  of  kerosene  is 
added;  this  keeps  down  the  froth  and  foam  that  will  otherwise 
result  when  the  saponification  products  (soaps)  of  the  cooking 
process,  which  have  been  absorbed  by  the  papers,  come  in  contact 
with  the  washing  cylinders  and  the  rapidly  revolving  circulating 
roll.  When  the  washer  has  been  completely  furnished,  the 
washing  cyhnders  are  lowered  and  the  wash  water  is  turned  on. 
The  amount  of  water  used  is  regulated  to  correspond  to  the 
volume  removed  by  the  cylinders;  thus  a  continuous  stream  of 
fresh,  clear  water  is  being  added  to  compensate  for  the  water 
removed,  which  is  laden  with  the  soluble  saponification  products, 
ink  and  dirt  particles. 

In  this  type  of  machine,  the  fresh  water  is  admitted  to  the 
stock,  sometimes  at  the  bottom  of  the  washer  and  in  back  of  the 
roll,  through  a  6-inch  pipe.  This  water  dilutes  the  stock,  passes 
up  through  it  and  out  by  the  revolving  C34inders,  and  goes  to 
waste.  Sometimes  the  water  is  introduced  in  front  of  the  roll, 
which  mixes  it  with  the  stock.  It  is  a  slow  process  of  constant 
dilution  of  the  impurities  of  the  cooking  action,  and  a  large 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        59 

volume  of  wash  water  is  required.  This  same  volume  of  wash 
water,  if  applied  to  the  stock  in  batches  of  equal  amounts  and 
then  removed,  thickening  the  stock  after  each  addition  of  fresh 
water,  would  greatly  lessen  the  time  of  washing  and  would 
produce  a  cleaner  pulp. 

106.  Removal  of  Dirt. — Bj^  the  constant  dilution  of  the  dirt, 
the  amount  of  dirt  remaining  in  the  pulp  is  gradually  lessened. 
This  progressive  action  continues  indefinitely;  but,  even  after 
the  stated  washing  period  has  expired,  the  stock  still  contains 
dirt,  though,  of  course,  only  a  very  small  amount.  If  at  this 
point,  a  sample  of  stock  be  taken  from  the  washer  and  subjected 
to  a  stream  of  fresh  water  on  a  small  hand  screen,  the  stock  will 
brighten  up  at  once  to  a  snow-white  color.  It  is  this  principle 
that  has  been  taken  advantage  of  in  the  modern  continuous 
washer. 

107.  Removal  of  Carbon  of  Inks. — If  the  paper  stock  has  been 
thoroughl}'  cooked,  the  carbon  of  the  inks  is  readily  removed. 
In  the  open-tank  process,  the  papers  still  retain,  largely,  their 
original  flat  shape  after  cooking;  hence,  on  immersing  a  sheet  of 
cooked  paper  in  water,  the  individual  letters  of  solid  carbon  can 
be  loosened  from  the  paper  by  gently  moving  the  sheet  to  and  fro. 
The  same  result  is  obtained  in  the  cooking  engine  by  the  action 
of  the  roll  on  the  papers,  the  friction  of  the  papers  against  the 
sides  and  bottom  of  the  tub,  and  against  the  cylinders;  the 
continual  rubbing  and  friction  in  the  mass  also  further  the 
removal  of  the  inks  and  the  formation  of  an  emulsion,  which  is 
readily  removed  in  the  wash  water. 

For  the  first  hour  of  washing,  the  wash  water  is  very  muddy 
and  dirty.  Continued  washing  clears  the  stock;  and  the  color 
gradually  changes  from  the  heavy  gray  tone  to  a  blue  white,  for 
ledger  stock,  or  to  a  cream  white  or  ocher  tint,  for  book  or 
magazine  stock. 

108.  Duration  of,  and  Effect  of,  Washing. — The  time  required 
for  a  thorough  washing  depends  on  a  number  of  factors.  The 
degree  of  cooking  that  the  paper  has  received  must  first  be 
considered.  If  well  cooked,  the  inks  will  readily  emulsify  with 
the  water;  but  if  the  paper  has  not  been  completely  cooked,  the 
ink  still  sticks,  or  perhaps  it  may  loosen  from  the  surface  of  the 
paper  and  be  found  later  in  the  finished  paper.  If  the  papers 
are  dry  cooked,  no  amount  of  washing  will  clear  the  ink  from  the 


60 


TREATMENT  OF  WASTE  PAPERS 


§2 


pulp;  and  after  being  bleached,  this  product  has  a  light  grayish 
tone,  similar  to  the  color  of  newspapers. 

109.  The  second  factor  to  be  considered  is  the  nature  of  the 
printing  inks.  It  has  been  found  that  ordinary  book  and  maga- 
zine inks  and  colors  are  easily  washed  out;  but  lithograph  and 
label  papers  that  contain  waterproof  inks  and  varnishes,  present 
greater  difficulties.  Solid  ledger  papers  arc  easilj^  washed  out; 
they  have  received  a  harder  treatment  in  cooking  to  dissolve  the 
hard  sizing,  the  inks  readily  emulsify,  and  a  clear,  blue-white 
pulp  is  obtained  with  about  2h  hours  of  washing,  ^  hour  for 
bleaching,  and  ^  to  1  hour  for  removing  bleach  residues. 

110.  The  third  factor  to  receive  consideration  is  the  composi- 
tion of  the  papers  to  be  washed.  Long-fibered  stock,  such  as 
writing  and  ledgers,  require  a  much  shorter  washing  period  than 


Fig.  18. 

the  short-fibered  book  stock.  The  fourth  factor  is  the  circulation 
of  the  stuff  in  the  washer  and  the  amount  of  water  used,  which 
influences  the  washing  period.  The  third  and  fourth  factors  are 
really  dependent  on  each  other,  for  the  larger  the  volume  of 
water  the  faster  the  stuff  will  circulate,  and  the  larger  the  volume 
of  water  used  the  greater  will  be  the  amount  of  dirt  and  ink 
removed  in  a  shorter  period. 

111.  When  the  paper  stock  is  considered  to  have  been  washed 
long  enough,  a  sample  of  the  wash  water  is  taken  out  and 
examined.  If  the  water  is  clear,  the  pulp  is  ready  for  bleaching; 
but  if  the  water  is  still  cloudy,  if  a  grayish  sediment  is  noticed, 
the  washing  must  continue  until  clear  fresh  water  is  obtained. 


§2        COOKING,  DE-TNKING  AND  DE-FIBERING        61 


The  first  washing  will 
generally  take  from  3  to 
3^  hours  for  the  usual  run 
of  paper  stock,  such  as 
book  and  magazine. 

Before  bleaching,  it  is 
well  to  concentrate  the 
stock  bj^  shutting  off  the 
water,  but  letting  the  cyl- 
inders run  for  a  time. 

112.  Other  Forms  of 
Washers. — In  Fig.  18,  is 
shown  a  machine  that  both 
washes  and  concentrates. 
The  agitators  A  keep  the 
stock  well  mixed,  and  the 
rotating  dippers  B,  which 
are  covered  with  wire  mesh 
(60  mesh  over  14  mesh), 
take  out  the  dirty  water  as 
fresh  water  is  added  at  W. 
On  shutting  off  the  fresh 
water,  the  stock  is  con- 
centrated, thus  saving 
bleach  and  storage  space. 
This  washer  handles  1500 
pounds  of  waste-paper 
stock  at  3  %  to  4  %  in  from 
2  to  3  hours;  it  requires 
about  6  h.p.  to  operate  it. 
Each  washing  cylinder  B 
is  driven  at  8  r.p.m.  by  a 
worm  gear  from  a  shaft  E. 
The  washed  stock  is  re- 
moved at  V. 

113.  Another  type  of 
washer,  which  is  meeting 
with  some  favor,  is  a 
slightly  inclined,  slowly 
rotating  cylinder  C  of  fine 
wire  cloth,  shown  in  Fig.  19. 


62 


TREATMENT  OF  WASTE  PAPERS 


§2 


The  stock  is  fed  in  at  one  end  and  is  distributed  by  worm  W; 
and  as  the  dirty  water  drains  out,  the  fibers  are  washed  with 
showers,  S,  finally  emerging  at  the  other  end.  Very  little  power 
is  required  to  operate  either  of  the  washers  just  described;  but 
practical  men  consider  them  to  be  wasteful  of  stock. 

114.  A  new  tj^pe  of  w^asher,  which  is  giving  good  results,  is  shown 
in  Fig.  20;  this  washer  is  very  effective  for  w^ashing  thick  stock 
rapidly.     It  is  better  to  wash  stock  when  it  is  thick,  if  the  water 


Fig.  20. 


can  be  removed;  because,  first,  there  is  less  stock  lost,  and,  second, 
on  account  of  the  small  amount  of  water  in  the  stock,  a  given 
quantity  of  water  added  or  removed  produces  a  greater  effect. 
S  (Fig.  20)  is  a  spout  through  which  dirty  water  is  discharged 
from  the  hollow  shaft  T  at  the  center  of  the  cylinder  C;  D  is  a 
worm  gear  for  lifting  the  washing  cj^linder  by  means  of  cables  E. 
This  washer  was  developed  as  a  feature  of  the  beater  shown 
in  Fig.  3,  which  is  also  used  as  a  washer  and  bleacher;  it  circu- 
lates stock  of  unusually  high  consistency.  The  small  view 
shows  the  assembled  washer,  in  which  G  is  the  gear,  belt  driven 
from  the  beater-roll  shaft. 


§2       COOKING,  DE-INKING  AND  DE-FIBERING       63 


64  TREATMENT  OF  WASTE  PAPERS  §2 

115.  A  Three -cylinder  Washer. — The  tendency  to  take  ad- 
vantage of  a  continuous  process  has  become  well-marked  in 
waste-paper  recovery;  and  much  attention  has  been  given  to  the 
three-cylinder  washer,  which  authorities  regard  as  the  ideal  type 
of  washing  machine. 

An  improved  washing  system  for  removing  ink  from  cooked 
waste  papers  is  shown  in  Fig.  21,  (a)  being  a  side  view  and  (h)  a 
top  view.  The  arrangement  consists  of  a  horizontal  stuff  chest, 
from  which  the  stock  is  lifted  at  a  uniform  rate  by  means  of  a 
bucket  wheel;  a  gravitator  (or  sand  trap),  the  feed  to  which  is 
controlled  by  a  gate;  a  centrifugal  screen,  for  removing  the  dirt 
not  caught  in  the  gravitator;  and  a  washing  machine,  which 
comprises  three  cylinder  units.  The  cylinder  in  each  unit  picks 
up  a  layer  of  stock  in  the  same  manner  as  a  pulp  thickener,  and 
delivers  it  to  a  couch  roll,  from  which  it  is  scraped  and  passed 
to  the  next  unit. 

The  water  consumption  is  small,  by  reason  of  the  economical 
way  in  which  the  water  is  handled,  and  80%  to  90%  of  the  ink 
is  removed  in  the  first  cylinder;  this  water  is  not  again  used  for 
washing.  The  water  from  the  second  cylinder  is  pumped  to  the 
stuff  chest  by  pump  B,  where  it  is  used  for  thinning  the  stock 
delivered  by  the  buckets.  The  water  from  the  third  cylinder, 
which  is,  of  course,  the  cleanest,  is  pumped  into  the  first  agitating 
trough  by  pump  A,  and  is  there  used  as  thinning  water.  The 
only  place  where  clean  fresh  water  is  used  is  in  the  final  washing 
operation,  which  occurs  in  the  last  agitating  trough. 


BLEACHING  THE  STOCK 

116.  Consumption  of  Bleach. — After  washing,  the  recovered 
pulp  is  ready  to  be  bleached.  For  a  washing  engine  of  1600 
pounds  capacity,  about  60  to  70  gallons  of  bleach  liquor  is  used  for 
book  and  magazine  stock.  The  hquor  should  test  6°Tw.  at  60°F., 
which  is  equivalent  to  about  |  pound  of  bleaching  powder  to  a 
gallon  of  liquor;  this  amounts  to  2  to  3  pounds  of  powder  to  100 
pounds  of  dry  papers.  This  volume  of  bleach  liquor  is  allowed  to 
act,  without  heating  the  pulp,  for  30  to  45  minutes,  and  it  should 
produce  a  snow-white  pulp.  By  taking  the  chill  off  the  water  and 
raising  the  temperature  to  about  80°  or  90°F.  (never  higher  than 
this),  the  bleaching  operation  may  be  greatly  shortened.  It  has 
been  found  by  trial  that  a  warm  bleaching  of  15  or  20  minutes 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        65 

duration  produces  very  efficient  results.  It  has  also  been  demon- 
strated that,  when  necessary, — such  an  occasion  arose  during  the 
World  War, — a  good  bleached  pulp  can  be  produced  with  0.6 
pounds  of  bleaching  powder  per  100  pounds  of  papers;  this 
amount,  however,  did  not  give  the  product  the  white  tone  that 
maj'  be  obtained  with  a  larger  consumption. 

After  giving  the  bleach  sufficient  time  to  act,  fresh  water  is 
turned  in,  the  cylinders  are  lowered,  and  the  bleach  residues  are 
completelj'  washed  out.  To  test  for  the  complete  extraction  of 
the  bleach,  the  well-known  test  of  starch  and  potassium  iodide 
is  applied;  any  chlorine  that  may  be  present  will  be  revealed  by 
a  distinct  blue  tint. 

117.  Bleaching  Stock  from  Special  Papers. — For  bleaching 
ledger  stock,  about  35  to  40  gallons  of  bleach  solution  for  10,000 
pounds  of  paper  is  required,  depending  on  the  quality  of  the  paper. 
A  thoroughl}'  Avashed,  solid  ledger  stock  presents  a  fine  blue-white 
appearance,  even  before  the  introduction  of  the  bleach  solution. 
The  mixed  ledger,  which  consists  of  letterheads,  invoices,  bills, 
letters,  and  other  similar  papers,  presents  a  motley  array  of 
colors,  and  it  requires  a  thorough  bleaching;  but,  even  then,  the 
resulting  pulp  has  a  faint  tone,  dependent  on  the  proportion  of 
the  strongest  colored  stock  present.  However,  with  the  excep- 
tion of  the  heavier  mineral  colors,  such  as  chrome-yellows, 
oranges,  greens,  umbers,  and  ochers,  the  colors  are  easilv  removed 
with  40  to  50  gallons  of  bleach  liquor.  The  bleaching  of  this  grade 
of  stock  requires  from  45  to  60  minutes  to  obtain  the  best  results. 

118.  Variation  in  Color  of  Bleached  Pulp. — It  is  quite  impos^ 
sible  to  obtain  a  strictly  uniform  color  in  the  bleached  paper 
stock.  There  is  such  a  wide  variation  in  the  composition  of  the 
papers  treated,  in  the  man}'  different  colors  present,  and  the 
variation  in  the  degree  of  cooking  in  different  parts  of  the  open 
tanks,  that  this  difference  is  to  be  expected.  A  simple  expedient, 
used  in  many  mills  to  obtain  a  good  sample  for  matching  pulp 
from  beater  to  beater,  is  the  following:  A  sample  of  pulp  is  taken 
from  the  beater  and  pressed  with  the  hands  into  a  ball,  about 
the  size  of  a  baseball.  With  practice,  it  is  very  simple  so  to  press 
all  the  sample  balls  that  each  will  have  very  nearly  the  same 
percentage  of  moisture.  By  breaking  a  ball  into  halves  and 
comparing  one  half  with  a  half  from  another  ball,  a  good  idea 
of  the  variation  between  the  two  mav  be  obtained.     (When  com- 


66  TREATMENT  OF  WASTE  PAPERS  §2 

paring  two  pulps,  it  is  very  important  that  both  have  the  same 
moisture  content.)  These  balls  can  be  stored  on  a  shelf,  marked 
with  the  beater  number  and  the  time,  and  can  then  be  inspected 
later  by  the  superintendent  and  foreman,  if  this  is  desired. 

It  is  the  practice  in  one  mill  to  dump  the  bleached  stock, 
together  with  the  bleached  residues,  into  tanks,  from  whence  it  is 
pumped  up  over  the  screens  and  back  to  the  drainers  (see  Fig.  15, 
Section  1),  where  the  stock  is  allowed  to  remain  until  all  the  sur- 
plus Kquor  drains  awaj^  and  the  drainer  is  filled.  In  this  way,  the 
bleach  residues  have  an  opportunity  to  become  dissipated  while 
oxidizing  an}'  organic  coloring  matter  that  may  still  remain  in  the 
stock.  The  door  to  the  drainer  is  then  opened,  the  pulp  is  forked 
into  cars  or  containers,  and  is  furnished  to  the  beaters.  When 
taking  stock  out  of  the  drainers,  it  is  removed  in  vertical  sections, 
so  that  the  various  tinted  strata  of  stock  may  be  kept  uniform  in 
all  the  beaters  furnished.  In  this  way,  it  is  simple  to  keep  the 
shade  of  the  finished  paper  constant.  If  the  pulp  is  put  into  the 
drainer  hot,  the  color  will  surely  deteriorate.  It  is  best  to  wash 
the  pulp  in  the  bleacher. 

119.  Use  of  Wet  Machine. — Another  method  in  vogue  is  to  run 
the  washed,  bleached,  and  screened  stock  over  a  wet  machine 
(fully  described  in  Section  1)  and  into  laps  of  pulp  of  about  25%  to 
30%  air-dry  fiber;  the  laps  are  stored  according  to  the  grade  of 
paper  and  the  resultant  shade.  This  method  of  handling 
screened  pulp  possesses  many  advantages,  and  was  adopted  by 
one  of  the  most  modern  book-paper  mills;  it  is  considered  to  be 
the  most  economical  and  efficient  method  in  use,  for  the  following 
reasons:  No  elaborate  pumping  systems  or  storage  tanks  are 
required;  the  loss  of  time  in  furnishing  the  beaters  with  diluted 
pulp  is  ehminated;  the  wet  machine  can  be  run  independently  of 
the  grade  of  stock  being  used ;  the  storage  of  the  pulp  ahead  of  the 
beaters,  and  the  possibility  of  an  immediate  change  from  one  grade 
of  paper  stock  to  another,  is  a  wonderful  saving  and  improvement ; 
the  ease  and  exactness  with  which  the  color  or  shade  of  the  paper 
made  on  the  machine  is  maintained. 


SHRINKAGE  OF  COOKED  PAPERS  ON  WASHING 

120.  Amount  of  Shrinkage. — The  shrinkage  of  paper  stock  on 
washing  has  always  been  a  stumbling  block  for  many  mills  that 
have  considered  the  adoption  of  cooked  paper  stock  for  a  part  of 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        67 

their  pulp  requirements.  The  exact  per  cent  of  shrinkage  has, 
perhaps,  never  been  worked  out  under  actual  mill-working 
conditions;  but  it  has  been  estimated  to  range  from  20%  to  40%. 
If  the  paper  treated  is  all  coated  paper,  practically  all  the  coating 
is  removed  by  the  de-fibering  and  washing  of  the  stock,  and  a 
shrinkage  of  40%  will  probably  result,  but  this  does  not  include 
the  loss  of  any  filler  that  may  be  present  in  the  raw  stock  before 
the  coating  was  applied,  which  amounts  to  5%  to  8%  additional. 
Toward  the  end  of  the  washing  process,  that  is,  when  the  wash 
liquor  is  free  from  dirt  and  contains  only  short  fibers,  it  is  usually 
considered  that  an  additional  loss  of  1  %  occurs  for  every  added  15 
minutes  of  washing.  Therefore,  it  is  not  advisable  to  wash  any 
longer  than  is  necessary  to  get  standard  color. 

Machine-made  paper  has  usually  received  a  thorough  beating 
or  refining  treatment.  The  individual  fibers  have  been  drawn  out 
and  cut  up  in  the  beaters,  and  the  refining  engine  again  reduces 
the  length  of  the  fibers,  when  necessary.  Then,  too,  bleached 
soda  pulp  is  quite  generally  used,  much  of  which  consists  of  fine 
or  short  fibers.  There  is  no  way  of  preventing  the  loss  of  most  of 
this  fine-filling  fiber,  if  the  stock  is  thoroughl}^  de-fibered  and 
washed  through  the  70-mesh  washing  cylinder  wire. 

121.  Limits  of  Shrinkage. — Numerous  ash  tests  have  been 
made  on  the  completely  washed  and  bleached  paper  stock,  and 
the  results  vary  from  2.5%  to  4%  total  ash.  When  this  percent- 
age is  compared  with  the  coating  ingredients  of  paper,  which 
amount  to  from  30%  to  40%  of  the  weight  of  the^paper,  the 
shrinkage  is  well  nigh  startling. 

Books  and  magazines  are  usually  printed  on  supercalendered 
paper,  which  contains  15%  to  20%  ash.  The  loss  in  ash  alone 
(not  reckoning  the  20%  of  bleached  soda  fiber  that  is  usually 
present)  thus  varies  from  15%-20%  to  2.5%-4%  which  shows, 
perhaps,  the  lowest  minimum  shrinkage.  In  solid  ledger  stock, 
the  shrinkage  is  largeh'  equivalent  to  the  loss  of  the  heav.y 
sizing, — both  animal  and  rosin  sizing, — because  the  stock  is 
usually  80%  to  100%  rags,  which  have  a  long  fiber.  The  remain- 
der of  the  fiber  composition  is  long-fiber  sulphite,  which  does  not 
entail  a  great  loss. 

It  is  safe  to  say  that  the  average  loss  in  washing  of  all  kinds  of 
paper,  well  mixed,  will  be  20%  to  30%. 


68  TREATMENT  OF  WASTE  PAPERS  §2 

SCREENING  WASHED  AND  BLEACHED  PAPER  STOCK 

122.  Importance  of  Screening. — After  the  old  paper  stock  has 
been  washed,  bleached,  and  dumped  into  storage  tanks,  it  is  ready 
to  be  screened,  which  is  the  fourth  very  important  step  in  the 
treatment  of  waste  papers,  although  it  is  an  almost  forgotten 
detail  in  some  mills. 

123.  Common  Form  of  Screen. — The  usual  screening  S3^stem 
in  American  mills  is  exceedingly  simple  and  is  frequently  inade- 
quate. One  flat  diaphragm  screen  of  six  plates,  each  plate  12 
inches  wide  and  40  inches  long,  is  considered  sufficient  to  screen 
stock  for  three  beaters  of  1000  pounds  capacity.  About  3.5  h.p. 
is  required  to  drive  a  screen  of  this  type.  The  stock  is  pumped 
up  from  the  storage  tanks,  at  a  consistency  of  about  3.5  ounces 
per  gallon  (equivalent  to  2.66%),  onto  sand  traps.  (For  disinfec- 
tion of  scums,  see  Section  7,  Vol.  Ill,  and  Section  6,  Vol.  IV, 
under  white  water.) 

124.  Sand  Traps. — A  common  sand  trap  is  24  inches  wide,  30 
to  40  feet  long,  and  12  inches  deep;  it  is  placed  8  to  10  feet 
above  the  beater-room  floor,  thus  allowing  free  passage  under- 
neath. The  bottom  of  the  sand  trap  is  lined  with  canvass,  such 
as  old  cotton  dryer  felt  from  the  paper  machine,  or  is  fitted  with 
cross  dams. 

The  purpose  of  these  long  narrow  boxes,  or  sand  traps,  is  to 
permit  the  heavier  particles  of  impurities  in  the  washed  stock  to 
settle  out  and  collect  on  the  rough  surface  of  the  dryer  felt,  or 
behind  the  dams.  The  efficiency  of  the  sand  traps  is  dependent 
on  the  dilution  of  the  stock,  the  rate  of  flow  over  the  course,  and 
the  length  of  the  course.  The  depth  of  the  stock  is  about  8  inches, 
the  slope  of  the  course  is  about  ^  inch  per  foot  of  length,  and 
longer  the  length  of  the  course  the  more  impurities  will  settle  the 
down. 

The  impurities  found  in  these  traps  are  mostly  pins  and  clips, 
such  as  are  attached  to  letters,  staples  and  fasteners  from  book 
backs,  rubber  bands,  bits  of  rags  and  strings,  sand  and  heavy 
pieces  of  grit.  A  film  of  fine  particles  of  iron  rust  is  found  to  be 
covering  most  of  the  drj^er  felt  bottom. 

125.  Furnishing  the  Beaters. — From  the  sand  trap,  the  stock 
may  go  back  to  the  chest,  or  through  the  screen  and  to  the  beater 
or  wet  machine.  When  the  beaters  are  ready  to  be  furnished,  the 
gate  to  the  screens  is  opened,  and  the  stock  from  the  sand  trap 


§2        COOKING,  DE-INKING  AND  DE-FIBERING        69 

flows  onto  the  screen.  Here  it  is  diluted  with  water,  to  separate 
fibers  from  impurities,  and  to  enable  the  stock  to  be  screened 
without  clogging  the  slots  and  flooding  the  entire  screening 
surface.  If  the  latter  should  occur,  an  overflow  is  arranged  to 
take  care  of  the  stock,  and  this  overflow  returns  the  stock  to  the 
storage  tanks. 

In  most  of  these  single  screens,  three  (3)  plates  are  cut  0.010 
inch  and  the  other  three  0.016  inch,  or  thereabouts.  The  density 
of  the  diluted  stock  as  it  is  furnished  to  the  beater  is  equivalent  to 
1.27%  furnish;  this  means  that  1  pound  of  dry  stock  is  diluted 
with  9.44  gallons  of  water,  since  1  4-  (9.44  X  8§)  =  0.0127 
=  1.27%.  To  furnish  600  pounds  of  dry  stock  at  this  dilution, 
the  washing  cylinders  in  the  beaters  must  remove  600  X  9.44 
=  5664  gallons  of  water,  which  requires  from  45  minutes  to  1  hour. 

Since  99  %  of  the  fine  dirt  particles  have  a  diameter  smaller  than 
0.016  inch,  they  have  free  passage  through  this  size  of  openings  in 
the  screen.  The  paper  made  from  this  screened  stock  is  sprinkled 
with  fine  dirt  particles,  and  the  quality  of  the  product  is  thereby 
lowered. 

126.  Effect  of  Poor  Screening. — By  far  the  largest  percentage  of 
the  materials  retained  on  the  screens  consists  of  small  bits  and 
particles  of  broke  or  paper,  which  have  not  been  completely 
de-fibered  in  the  washing  engine.  The  amount  of  this  material  in 
the  screenings  has  startled  many  mill  superintendents;  but, 
instead  of  remedjdng  the  trouble,  they  have  side-stepped  it  by 
increasing  the  size  of  the  screen  cuts,  in  some  instances  up  to 
0.028  inch.  This,  of  course,  cuts  down  the  amount  of  screened 
undefibered  stock  somewhat.  An  attempt  is  made  to  clear  or 
finish  the  de-fibering  of  this  stock  in  the  beater  and,  later, 
by  refining  it  shorter  in  the  Jordan  engine.  This  method  may 
work  part  of  the  time ;  but,  occasionally,  the  increased  production 
of  the  paper  machine  calls  for  more  stock,  in  which  case,  the 
beaters  are  crowded  and  cannot  condition  the  stock  in  the  same 
degree.  Then,  too,  when  the  stock  is  run  long,  that  is,  when  a 
good  strong-fibered  sheet  is  required,  very  little  beating  is 
necessary,  except  to  clear  the  sulphite  or  soda  pulps  used,  and  the 
Jordan  engine  action  is  reduced  almost  to  a  bare  clearing  of  the 
stock.  The  result  is  that  the  finished  sheet  is  sprinkled  with 
these  particles  of  undefibered  stock  of  varying  size.  At  times, 
they  are  so  much  in  evidence  that  they  are  the  cause  of  the  sheet 
breaking  down  at  the  wet  presses,  and  offer  untold  difficulties  in 


70  TREATMENT  OF  WASTE  PAPERS  §2 

carrying  the  sheet  over  to  the  calenders,  besides  being  a  means  of 
carrying  ink  particles  into  the  paper.  The  reason  for  this  break- 
ing down  is  explained  by  the  fact  that  the  particles  of  broke  have 
no  felting  power,  and  whenever  they  are  present,  they  produce  a 
weakened  spot  in  the  sheet.  On  going  through  the  calenders, 
these  are  made  transparent,  and  they  stand  out  quite  distinctly 
in  the  finished  sheet.  This  defect  in  the  finished  paper,  especiallj- 
in  coated  paper,  results  in  sheets  of  lower  quality,  or  seconds.  . 


QUESTIONS 

(1)  What  factors  influence  the  rate  and  completeness  of  washing  old  paper 
stock? 

(2)  About  how  much  bleaching  powder  is  required  to  bleach,  in  pulp  form, 
100  lb.  of  dry  papers? 

(3)  What  is  your  opinion  of  the  suggestion  to  use  a  wet  machine  in  the 
handling  of  cooked  waste  paper  stock? 

(4)  What  kind  of  equipment  is  used  in  screening  waste  paper  stock? 
Explain  the  importance  of  this  operation. 


TREATMENT  OF  WASTE 
PAPERS 


EXAMINATION  QUESTIONS 

(1)  Mention  some  reasons  for  the  extensive  use  of  waste  papers. 

(2)  (a)  What  chemical  action  takes  place  in  the  removal  of 
printing  ink?     (6)  What  kind  of  chemical  is  used? 

(3)  What  are  the  four  principal  classes  of  waste  papers? 

(4)  Name  the  principal  operations  in  treating  waste  papers  for 
paper  making, 

(5)  Describe,  with  sketch,  one  type  of  waste-paper  duster,  and 
tell  how  it  works. 

(6)  What  becomes  of  the  discards  from  the  sorting  room? 

(7)  Explain  the  term  dry  cook  and  the  result  of  a  dry  cook. 

(8)  If  you  were  planning  a  mill,  would  you  consider  the 
recovery  of  soda-ash  liquor  an  important  factor?  Give  reasons 
for  your  answer. 

(9)  (a)  What  are  the  three  principal  factors  in  cooking?  (6)  how 
does  a  change  in  one  affect  the  other  two? 

(10)  What  influence  would  the  cost  of  power  exert  in  connec- 
tion with  the  selection  of  the  cooking-engine  process? 

(11)  (a)  If  the  consistency  of  a  900-lb.  batch  of  papers  being 
cooked  is  5%,  what  is  the  total  weight  of  the  charge?  (6)  How 
much  of  the  charge  is  water,  allowing  for  the  soda  ash 

found  in  (a)?  /18,000  1b. 

^'^-    [  17,055  lb. 

(12)  Taking  1  B.t.u.  as  the  heat  required  to  raise  the  tempera- 
ture of  1  lb.  of  water  1°F.,  and  assuming  paper  and  soda  ash 
to  have  the  same  specific  heat  as  water,  how  many  heat  units 
will  be  required  to  raise  the  temperature  of  a  batch  containing 
900  lb.  of  paper  and  chemical,  at  5%  consistency,  from  45°  to 
175°F.?  Ans.  2,340,000  B.t.u. 

(13)  What  test  shows  when  bleach  residues  have  been  washed 
out  of  the  stock? 

§2  71 


72  TREATMENT  OF  WASTE  PAPERS  §2 

(14)  (a)  Give  maximum,  minimum,  and  average  losses  in 
washing  old  paper  stock.  (6)  Mention  some  sources  of  these 
losses. 

(15)  (a)  Which  method  of  cooking  old  waste  papers  is  most 
popular?  (6)  Which  method  do  you  consider  best?  Give 
reasons. 


SECTION  3 

BEATING  AND  REFINING 

By  Arthur  B,  Green,  A.B.,  S.B. 

WITH  Bibliography 

By  C.  J.  West,  Ph.D. 


INTRODUCTION 

1.  The  Preparation  and  Supply  of  Stock  for  the  Paper  Machine. 
The  two  operations  of  beating  and  refining  also  accomplish  the 
necessary  mixing  of  the  various  materials  that  are  to  go  into 
the  final  paper,  and  also  the  necessary  reduction  of  the  pulps,  or 
fibrous  materials,  to  such  a  state  that  they  will  form  themselves 
into  a  sheet  of  the  desired  characteristics.  As  for  the  many 
classes  of  pulps,  the  sources  from  which  they  are  derived,  the 
processes  by  which  they  are  extracted  from  nature,  and  the 
processes  by  which  they  are  purified  and  whitened,  these  have 
already  been  dealt  with  in  preceding  sections.  These  processes 
fit  the  different  pulps  in  various  ways  for  the  operation  of  beating. 
They  may  or  may  not  be  carried  on  in  the  same  works,  or  under 
the  same  management,  as  the  beating  and  refining  themselves; 
but  wherever  beating  and  refining  are  carried  on,  they  represent 
the  first  step  in  the  actual  making  of  paper,  and  are  always 
included  in  the  same  works,  and  under  the  same  management,  as 
the  paper  machines,  which  transform  pulp  into  paper. 

Beating  and  refining  are  different  processes.  Where  they  are 
both  carried  on,  however,  they  are  for  the  same  purpose,  and 
constitute  two  successive  steps  in  the  preparation  of  the  stock 
for  the  paper  machine.     Refining  is  not  always  done;  but,  with 

Note. — Special  acknowledgement  is  hereby  made  to  Frederick  A.  Curtis, 
of  the  United  States  Bureau  of  Standards,  for  valuable  assistance  in  the 
revision  and  arrangement  of  the  manuscript  and  in  the  preparation  of  the 
photo-micrographs. 
§3  1 


2  BEATING  AND  REFINING  §3 

very  few  exceptions  indeed,  there  is  always  something  in  the 
nature  of  beating  as  the  first  step  in  making  paper  from  pulp. 
In  some  grades  of  paper,  the  amount  of  beating  required  is  so 
slight  that  the  process  has  degenerated  from  a  highly  skilled 
operation  to  hardly  more  than  proportioning  and  mixing,  carried 
out  almost  automatical!}-.  Newsprint  is  one  of  these  grades,  and 
great  tonnage  of  paper  is  made  every  day  with  no  more  beating 
than  this.  Nevertheless,  in  higher,  more  expensive,  grades  of 
paper,  it  is  the  beating  that  largeh'  determines  the  quality  and 
value  of  the  final  product. 

2.  Beating  Defined. — Beating  is  a  general  term  for  the 
mechanical  treatment  given  to  paper-making  materials  suspended 
in  water,  to  mix  them  and  to  prepare  them  for  forming  on  the 
paper  machine  a  paper  of  the  desired  character.  Refining  is  a 
further  mechanical  treatment,  which  usually  follows  the  beating 
or  mixing,  to  complete  the  preparation  of  the  materials. 

The  beater  and  the  refiner  are  different  pieces  of  equipment. 
There  is  usually  more  than  one  beater  for  one  paper  machine,  the 
several  beaters  being  furnished  and  dumped  in  rotation,  all 
discharging  to  a  common  chest  on  the  floor  below.  Thus  beating 
is  done  in  batches,  and  comes  under  the  class  of  processes  known 
as  "batch"  processes.  The  chest  on  the  lower  floor  serves  as  a 
reservoir  from  which  the  beaten  stock  is  pumped  up  to  the 
refiner  in  one  continuous  stream,  and  thus  it  passes  continuously 
through  the  refiner.  Refining  falls  under  the  class  known  as 
"continuous"  processes.  There  may  be  one  refiner  for  one 
paper  machine,  or  there  may  be  several;  in  the  latter  case,  they 
may  work  in  parallel  for  capacity,  or  in  series  for  maximum 
action  on  the  fiber. 

It  is  at  the  beater  that  the  materials  which  are  to  impart  to 
the  final  paper  its  color,  opacity,  sizing,  etc.  are  added  to  the 
fibrous  pulps.  These  materials  are  not  pulps;  they  are  non- 
fibrous.  Their  action  and  their  effect  is  partly  physical  and 
partly  chemical. 

3.  History  of  Beating. — Not  all  of  the  facts  are  known  that 
would  be  necessary  to  fix  the  exact  time  and  place  of  the  first 
use  of  beating.  The  verj'-  early  papers  made  in  China  were 
fashioned  from  fibers  of  the  inner  bark  of  certain  trees;  and  the 
nature  of  these  fibers  allowed  of  enmeshing  them  into  a  sheet 
without  beating,  so  long  as  the  work  was  done  by  hand  and  the 


§3  INTRODUCTION  3 

uses  of  paper  were  confined  to  such  qualities  as  could  be  produced 
in  this  way.  In  the  eighth  century,  the  art  spread  from  the 
Chinese  to  the  Arabs,  then  from  the  Arabs  to  the  Greeks  and 
Moors,  and  reached  Europe  in  the  thirteenth  century,  by  which 
time,  rags  had  become  so  general  as  raw  material  for  paper  as  to 
make  it  certain  that  some  beating  must  have  been  done  before 
the  fibers  were  ready  for  the  hand  mold. 

The  early  process  for  reducing  cotton  rags  to  pulp  consisted 
first  of  rotting,  next  washing  in  open  streams  in  bags,  and  finally 
pounding,  either  with  mortar  and  pestle,  or  on  stone  surfaces 
with  hard  wooden  implements.  The  pounding  was  hand  labor; 
but  before  the  eighteenth  centurj^,  machiner}-  was  devised  for 
doing  the  pounding;  that  is,  heavy  wooden  stampers  were  fitted 
to  a  row  of  upright  cylinders,  or  pans,  made  of  wood  or  stone, 
and  by  means  of  trippers  attached  to  a  shaft  driven  by  a  water- 
wheel  these  stampers  were  raised  and  allowed  to  fall.  This  was 
known  as  the  stamping  mill. 

These  stampers  were  divided  into  three  groups :  The  first  group 
were  shod  with  heavy  iron  teeth  or  nails,  to  tear  the  rags ;  the 
second  group  were  shod  with  finer  teeth  to  draw  out  the  fibers; 
and  the  third  group  were  of  hard  wood,  weighted  but  not  shod, 
and  served  to  bruise  the  fibers.  Fresh  running  water  in  the  first 
two  groups  of  pans  washed  the  rags  through  holes  in  the  bottom, 
covered  with  fine  hair-cloth.  It  is  said  that  this  process  of 
beating  took  about  32  hours,  and  that  a  mill  with  six  pans  could 
produce  about  500  pounds  a  week.  Fibers  treated  by  these 
earh'  processes  went  into  the  paper  very  much  greater  in  length 
than  is  the  case  with  any  grades  of  modern  paper ;  and  the  sheets 
that  have  been  preserved  from  early  times  show  remarkable 
strength. 

4.  Invention  of  the  Hollander. — About  the  middle  of  the 
eighteenth  century  one  of  the  great  steps  was  taken  in  the 
advancement  of  the  paper-making  art  when  the  Hollander  beater 
was  developed  in  Holland  to  replace  the  stamping  mill.  It  was 
claimed  that  two  beaters  could  be  run  by  the  power  required  for  one 
set  of  stamps.  Instead  of  the  row  of  cylinders  or  pans,  there 
was  an  open  tub,  roughly  oblong,  with  ends  rounded,  and  with  a 
partition  in  the  center,  built  parallel  with  the  straight  sides, 
allowing  continuous  flow  of  the  pulp  along  one  side,  around  the 
end,  along  the  other  side,  and  around  the  other  end.  On  one 
side  of  the  partition,  a  roll  was  mounted  on  a  heavy  spindle, 


4  BEATING  AND  REFINING  §3 

which  extended  across  the  tub  at  right  angles  with  the  long  side. 
Under  the  roll  was  built  a  suitable  bed-plate;  and  both  roll  and 
bed-plate  were  fitted  with  bars  of  metal.  Near  the  roll,  on  the 
side  turning  upward,  was  built  a  back-fall,  over  which  the  roll 
would  throw  the  pulp,  and  over  the  roll  was  a  hood  to  confine  the 
splash.  Thus,  as  the  roll  was  turned  rapidly  in  close  bearing 
upon  the  bed-plate,  the  pulp  was  propelled  around  the  open  tub, 
and  passed  repeatedh^  under  the  roll.  The  Hollander  is  the  type 
of  beater  in  common  use  today;  and  in  principle  it  has  not  been 
changed  since  its  invention,  nearly  two  hundred  years  ago. 


BEATER  CONSTRUCTION  AND  OPERATION 


TYPES  OF  BEATERS 

5.  General  Considerations. — Although  beating,  as  a  necessary 
means  of  preparation  of  the  stuff,  has  been  in  use  for  three 
centuries  or  more,  nevertheless  it  is  not  yet  possible  to  state 
accurately  what  the  beater  accomplishes.  Brushing,  cutting, 
bruising,  brooming,  hydrating,  attrition,  are  among  the  terms 
used  to  describe  what  happens  to  the  fiber  in  the  course  of  beater 
treatment,  but  these  are  general  terms,  and  it  is  impossible  to 
say  how  many  of  them  apply  to  the  beating  of  any  particular 
kind  of  stuff,  ^  or  in  what  proportions  these  various  actions  take 
place.  This  phase  of  the  subject  will  have  further  treatment  in 
later  parts  of  this  Section,  under  the  heading  Theory  of  Beating; 
but  in  considering  the  various  designs  of  beating  equipment  now 
to  be  described,  it  should  be  born  in  mind  that  none  of  them  can 
be  said  to  be  based  on  accurate  knowledge  of  the  beating  action. 

The  different  types  of  beaters  are  described  roughly  in  the 
order  of  the  extent  to  which  they  are  used.  The  first,  the  Hol- 
lander, now  generally  written  Hollander,  is  by  far  the  most 
prevalent. 

1  Stuff  is  the  name  given  to  fibrous  paper-making  materials  after  mixture 
with  whatever  non-fibrous  substances  are  used  and  after  beating  and 
refining,  ready  for  the  paper  machine.  These  materials  are  in  suspension 
in  water.  The  milky  mixture  flowing  out  on  the  paper  machine  is  also  called 
stuff,  but  in  this  book  it  will  be  called  stock.  It  has  been  modified  from 
the  beaten  and  refined  state  only  by  dilution  with  water  and  with  back- 
water from  the  machine.  Pulps  ready  to  furnish  to  the  beater,  particularly 
in  fine  paper  mills,  are  called  half-stufif. 


§3   BEATER  CONSTRUCTION  AND  OPERATION    5 

THE  HOLLANDER 

6.  The  Hollander  Tub. — The  tub  of  the  Hollander  consists 
of  an  open  vessel,  built  usually  of  wood  or  cast  iron,  the  wooden 
construction  being  shown  at  A,  Fig.  1.     The  rounded   ends  of 


the  tub,  in  conjunction  with  the  central  partition  B,  called  the 
midfeather,  or  midboard,  form  the  channel  through  which  the 
stock  travels  in  continuous  circuit.  In  later  types,  the  tub  has 
been  made  of  concrete,  though  this  has  been  used  more  often 
where  the  design  of  the  tub  is  more  complex,  that  is,  in  other 
designs  of  beaters.  The  cast-iron  tub  is  best  adapted  where  heat 
is  used  in  the  beater  to  assist  in  disintegrating  okl-paper  stock, 
as  in  board  mills.     In  mills  making  fine  papers,  where  color  and 


6  BEATING  AND  REFINING  §3 

cleanliness  are  prime  requirements,  beater  tubs  are  lined  with 
sheet  copper  and  beater  bars  and  bed-plate  knives  are  made  of  a 
non-corroding  metal  such  as  bronze.  A  Hollander  beater 
measuring  approximately  20  feet  long  and  9  feet  wide,  with  sides 
about  3  feet  6  inches  high,  will  hold  approximately  1350  pounds 
of  air-dry  stock  at  a  consistency  of  about  5%. 

An  integral  part  of  the  beater  tub  is  the  back-fall  G,  shaped  on 
one  side  to  conform  to  the  curve  of  the  beater  roll,  and  having  on 
the  other  side  a  steep  slope.  The  roll  throws  the  stuff  over  its 
crest,  thus  forming  a  head,  so  that  the  force  of  gravity  causes  the 
stuff  to  travel  away  from  the  roll,  around  the  tub,  and  thus  back 
to  the  roll  again.  This  travel  is  called  circulation,  and  stuff 
circulating  in  the  beater  tub  is  said  to  turn.  Due  partly  to  the 
use  of  short-fibered  stocks  in  recent  years,  the  design  of  the  tub 
and  back-fall  is  receiving  considerable  study,  and  many  modifica- 
tions are  now  offered,  without  departing  from  the  Hollander 
type,  to  secure  more  rapid  circulation  and  beating. 

7.  In  some  beaters,  as  an  aid  in  dumping  the  stock,  water  may 
be  introduced  at  the  base  of  the  back-fall,  as  shown  at  W.  For 
certain  kinds  of  stock,  especially  with  rag  half-stuff,  the  beater 
is  equipped  with  a  narrow  metal  box  jT,  Fig.  1  (6),  set  in  the  floor 
and  covered  with  a  perforated  plate.  This  acts  as  a  trap  for 
heavy  particles  of  metal,  dirt,  or  sand,  and  is  called  a  sand  trap. 
It  is  cleaned  through  a  small  opening  to  the  sewer  or  by  hand. 
Valve  y  is  a  sewer  connection  for  cleaning  out  the  tub,  and  V  is 
a  valve  for  emptying,  or  dumping,  the  beaten  stock  to  the 
chest.  In  most  cases,  these  valves  consist  essentially  of  a  heavy 
metal  plate  or  disk,  fitting  into  the  opening  with  a  ground  joint. 
In  some  recent  designs,  the  dumping  valve  may  extend  from  the 
front  side  to  the  midfeather  and  be  so  designed  that,  when  the  cover 
is  raised,  it  acts  as  a  baffle  to  deflect  the  stock  to  the  opening. 

In  Fig.  1  (6),  it  will  be  noticed  that  the  bottom  of  the  tub  is 
flat,  and  that  there  is  only  a  small  fillet  around  the  bottom  of  the 
tub  and  midfeather  where  it  is  joined  to  the  sides  of  the  tub.  An 
increased  speed  of  circulation  and  a  higher  concentration  or 
density  (consistency)  of  stock  are  rendered  possible  by  raising  the 
bottom  of  the  back-fall  at  W  higher  than  the  bottom  of  the  tub  at 
Y  or  T,  thus  permitting  a  gentle  slope  for  the  stock.  Lodging 
of  inert  or  dead  stock  in  the  corners  can  be  avoided  by  having 
the  bottom  of  the  tub  U  shaped,  as  can  be  readily  done  with  con- 
crete construction. 


§3      BEATER  CONSTRUCTION  AND  OPERATION         7 

8.  Beater  Roll  and  Bars. — A  heavy  spindle  C  is  mounted  across 
the  tub  at  right  angles  to  the  midfeather,  and  is  supported  in 
bearings  at  its  ends,  the  bearings  resting  in  lighter  bars  D.  To 
this  spindle  is  firmly  attached  the  beater  roll  R,  usually  called 
the  roll.  The  spindle  and  roll  are  revolved  by  means  of  a  belt  or 
chain  drive  from  a  constant  speed  shaft  or  motor  to  a  large  pulley 
on  the  back  side  of  the  tub.  This  pulley  may  be  either  inside  or 
outside  the  back-side  lighter  bar. 

9.  The  typical  beater  roll  is  built  on  three  or  more  cast-iron 
spiders  A,  Fig.  2,  which  are  keyed  to  the  roll  spindle  B.  The 
spiders  are  slotted  to  receive  the  fly  bars  C.     These  bars  are 


Fig.  2. 

themselves  slotted  at  both  ends,  as  shown  in  detail  at  (6),  for  the 
hoop  or  band  D  by  which  the  bars  are  usually  held  in  place  and 
kept  from  flying  off  at  a  tangent.  The  bars  may  be  evenlj- 
spaced  or  set  in  clusters,  the  arrangement  and  number  varying 
with  the  kind  of  stock  to  be  beaten  and  the  kind  of  paper  to  be 
made.  Wooden  blocks  E,  cut  slightly  wedge  shape,  and  called 
filling,  are  driven  tightly  between  the  bars.  This  filling  is  made 
from  dry,  well-seasoned,  hard  wood;  and  the  water  in  the  tub 
produces  a  swelling  of  the  wood,  which  tends  to  hold  the  bars 
fast  and  prevent  vibration.  There  are,  however,  several  methods 
of  fastening  the  bars  C  to  the  spiders  A.  In  one  case,  the  bar 
is  dropped  into  a  notch  in  each  spider,  and  is  fastened  in  place  by 
driUing  a  hole  in  the  bar  over  a  pin  or  lug  in  the  side  of  the  notch, 
the  bar  being  firmly  held  by  pouring  in  a  low  melting  alloy,  or  by 
screwing  down  a  wedge.  In  other  cases,  the  bars  are  held  in 
place  by  a  circular  plate  or  hoop  D,  which  is  firmly  bolted  to  the 
outside  spiders,  and  by  a  driven  fit  in  the  slots  of  the  spiders. 


8  BEATING  AND  REFINING  §3 

The  beater  roll  R,  Fig.  1,  is  so  designed  that  its  width  (face) 
nearl}^  fills  the  space  between  one  side  of  the  beater  tub  and  the 
midfeather.  It  may  weigh,  together  with  the  spindle  and  pulley, 
from  3000  to  6000  pounds  and  may  be  revolved  at  a  peripheral 
speed  of  from  1500  to  2500  feet  per  minute.  The  width  and 
diameter  of  the  roll  depend  upon  the  dimensions  of  the  beater. 

10.  In  most  cases,  the  beater-roll  bars  are  made  of  metal;  steel 
is  in  most  common  use,  though  bronze,  manganese  bronze, 
phosphor  bronze  and  manganese  steel  are  also  used.  A  new 
design  provides  a  cylindrical  shell  with  the  bars  on  the  outside  and 
spiders  inside,  all  cast  in  one  piece,  and  the  bar  edges  turned 
true.  Since  different  kinds  of  stock  need  different  beating 
treatment,  it  is  necessary  to  consider  the  quality  of  the  bars  for 
the  particular  stock  to  be  beaten.  For  certain  papers  where  the 
stock  has  to  be  beaten  very  "wet, "  such  as  glassine,  or  where  the 
paper  must  be  free  from  metal  particles,  such  as  sensitizing  paper 
and  condenser  paper,  a  stone  roll  is  of  value,  because  iron  causes 
rust  spots,  discoloration  of  tints,  etc.  This  latter  type  of  roll  is 
usually  made  of  basalt  lava  or  a  mixture  of  concrete  and  quartz, 
and  may  be  built  up  by  using  narrow  blocks  that  are  held  to  the 
spiders  by  pins  or  bolts.  Blocks  of  porous  cast  iron  may  be 
employed  in  the  same  way.  It  is  possible,  however,  for  a  roll  to 
be  cut  out  of  a  block  of  basalt  lava,  or  to  be  built  up  with  concrete 
and  flint  on  an  old  roll,  by  removing  some  of  the  bars  and  using 
the  others  for  a  bond. 

11.  In  order  to  prevent  loss  of  the  stock  that  is  carried  around 
between  the  bars  of  the  roll,  a  covering  E,  called  a  hood  or  curb,  is 
placed  over  the  roll.  This,  in  part,  conforms  to  the  shape  of  the 
roll  and  extends  back  and  down  the  sides,  and  is  firmly  bolted  to 
the  sides  of  the  beater  tub.  To  facilitate  the  circulation  of  the 
stock  and  to  prevent  if  from  being  carried  over  the  top  of  the  roll, 
a  baffle  F  is  attached  to  the  curb  to  deflect  the  stock  over  the  back- 
fall. The  design  of  the  curb  and  baffle  is  of  great  importance,  as 
will  be  brought  out  later. 

12.  The  Bed -Plate. — Directly  beneath  the  roll  is  the  bed- 
plate H,  Fig.  1,  frequently  called  the  plate;  it  is  set  in  a  chair  or 
box  by  means  of  wooden  wedges  accurately  parallel  to  the  axis 
of  the  roll.  The  bed-plate.  Fig.  2  (c)  and  (d),  is  made  up  of  strips 
of  metal  or  bars  F,  set  on  edge,  spaced  with  wood  filling  G,  and 
firmly  bolted  together  at  H.     This  is  shown  in  large  detail  at  (e). 


§3      BEATER  CONSTRUCTION  AND  OPERATION        9 

These  plates  may  be  elbow  plates,  as  shown  at  (c),  or  may  be 
straight,  as  shown  at  (d),  and  set  at  a  slight  angle  to  the  axis  of 
the  roll,  or  may  take  one  of  numerous  other  forms.  The  plate 
and  plate  box,  or  chair,  are  so  designed  that  the  plate  may  be 
removed  through  an  opening  in  the  side  of  the  beater  when 
necessar}^  by  removing  a  bolted  cover  plate. 

13.  The  Roll-adjusting  Mechanism. — In  the  operation  of  the 
beater,  the  only  adjustment  made  after  beating  begins  is  the 
raising  or  lowering  of  the  roll;  the  mechanism  for  accomplishing 
this  is  shown  in  detail  at  (c),  Fig.  1.  The  lighter-bar  D  is  pivoted 
at  one  end  at  0;  the  other  end  rests  on  a  nut  N  that  runs  on  a 
vertical  threaded  rod  K,  between  guides  in  the  lighter  stand, 
which  keep  the  nut  from  turning.  At  the  upper  end  of  the  rod 
X  is  a  worm  gear  L;  this  engages  with  a  worm  on  the  shaft  J, 
which  extends  across  both  lighter  stands,  and  is  turned  by  means 
of  the  wheel  M.  In  this  manner,  a  very  minute  vertical  adjust- 
ment is  given  to  the  end  of  the  lighter-bar  D.  Since  the  bearing 
that  supports  the  spindle  C  is  at  the  middle  of  the  lighter-bar,  the 
spindle  receives  just  one-half  of  this  adjustment.  One  turn  of  the 
hand  wheel  M  raises  or  lowers  the  beater  roll  approximately  one 
one-hundreth  of  an  inch.  Bevel  gears  may  be,  but  seldom  are, 
used  in  place  of  the  worm  gear  and  worm.  At  Z  is  a  spiral  cam. 
In  case  of  an  emergency,  a  pull  on  handle  X  will  raise  the  roll  one- 
half  inch  or  more. 


SPECIAL  TYPES  OF  BEATERS 

14.  Defects  of  the  Hollander. — There  are  a  number  of  grounds 
for  criticising  the  modern  Hollander  beater,  among  which  are: 
larger  power  consumption;  low  beating  capacity;  insufficient 
mixing  of  the  various  ingredients  of  the  furnish;  large  floor  space 
required;  and  lack  of  close  control  over  the  beating  operation. 
During  the  past  fifty  years  there  have  been  numerous  attempts 
to  improve  on  the  design  of  the  Hollander.  These  attempts 
have  resulted  in  a  large  variety  of  engines  of  various  kinds,  which 
are  being  used  to  a  greater  or  less  degree.  Some  of  the  more 
important  types  will  now  be  described  in  detail. 

15.  The  Home  Beater. — One  of  the  functions  of  a  beater  is 
that  of  mixing,  and  the  ordinary  Hollander  beater  was  found  to 
be  faulty  in  this  respect.  By  referring  again  to  Fig.  1,  it  may 
be  inferred  from  the  plan  view  (a)  that  portions  of  the  stuff 


10 


BEATING  AXD  REFINING 


§3 


flowing  next  to  the  midfeather  will  remain  there  indefinitely, 
for  there  is  nothing  to  throw  them  to  the  outside;  and  this  will 
be  found  to  be  the  case.  The  Home  beater  (patented  in  August, 
1886)  was  designed  to  overcome  this  deficiencj%  and  is  illustrated 
in  Fig.  3.  Instead  of  running  with  its  top  above  the  surface  of 
the  stock,  as  in  the  Hollander,  the  beater  roll  R  is  submerged, 
and  instead  of  being  placed  at  the  center  of  the  tub,  it  is  located 
at  one  end.     The  midfeather  M,  as  it  approaches  the  roll,  is 


Fig.  3.^ 

turned  across  the  tub  at  BC,  where  the  top  joins  the  back-fall 
T,  which  ends  in  a  shoe  S  that  acts  as  a  doctor,  to  deflect  the  stock 
from  the  roll.  Thus  the  stock  is  carried  between  the  roll  R  and 
the  bed-plate  P,  thence  around  and  over  the  roll,  where  it  is 
deflected  by  the  shoe  S,  and  is  sent  back  on  the  other  side  of  the 
midfeather  and  under  the  back-fall  at  AB,  to  the  roll  again. 
The  back-fall  creates  the  head  that  forces  the  stock  around  the 
tub.  As  the  stock  nears  the  roll,  the  channel  through  which  it  is 
traveling  becomes  wider  and  shallower,  finally  reaching  a  width 
equal  to  that  of  the  roll.  Those  portions  of  the  stock,  therefore, 
which  approach  the  roll  from  a  position  next  to  the  midfeather, 
actually  return  from  the  roll  in  a  position  next  to  the  outside  of 


§3      BEATER  CONSTRUCTION  AND  OPERATION       11 


the  tub.     This  action  may  be  readily  observed  in  a  mill  when 
the  beaterman  puts  in  the  colors. 

As  the  head  of  stuff  over  the  shoe  may,  under  some  conditions, 
be  considerable,  the  return  side  of  the  tub  is  covered  with  stout 
plank  E,  which  extends  nearlj^  to  the  end  of  the  midfeather, 
where  the  sectional  area  of  the  channel  again  becomes  normal. 
The  roll  is  carried  and  adjusted  by  the  same  type  of  mechanism 
that  is  used  with  the  Hollander. 

16.  The  Umpherston  Beater. — Another  deficiency  of  the 
Hollander  beater  is  the  large  floor  area  required  to  operate 


Fig.  4. 

it.  There  have  been  many  attempts  to  improve  upon  the 
Hollander  in  this  respect,  notably  in  the  Taylor  and  the 
Umpherston  beaters.  The  Taylor  is  rarely  found  in  use  now. 
but  the  Umpherston  is  on  the  market,  and  is  not  uncommon, 


12 


BEATING  AND  REFINING 


§3 


In  both  of  these  types,  it  is  sought  to  economize  floor  space  bj' 
circulating  the  stock,  not  in  a  horizontal  path,  but  in  a  vertical 
one,  passing  downward  through  the  floor  and  up  again  on  the 
return. 

The  Umpherston  beater  is  illustrated  in  Fig.  4.  The  tub, 
made  of  cast  iron,  is  in  the  form  of  a  shell,  in  two  parts,  set  into 
the  floor  up  to  the  level  of  the  flanges  F,  where  the  two  halves 
of  the  tub  are  fastened  together.  The  midfeather  M  and  the 
back-fall  B  are  one  piece,  set  in  a  horizontal  position;  and  in  the 
same  casting  is  carried  the  chair  for  the  bed-plate  P.  The  stock 
is  furnished  at  A  and  dumped  through  the  spout  at  D.  The 
cast-iron  fitting  through  which  the  dumping  is  effected  is  provided 
with  a  packing  gland  G,  through  which  runs  a  vertical  spindle. 
The  spindle  operates  a  cap,  or  plug,  fastened  to  its  upper  end, 
and  raises  the  cap,  to  allow  the  stock  to  drop;  it  is  also  connected 
by  a  lever  to  a  handle  above  the  floor,  which  operates  the  valve. 
The  roll  R  is  shown  conventionally. 

17.  The  bed-plate  is  set  in  a  cast-iron  chair,  or  box,  as  in  other 
types  of  beaters,   and  is  driven  to  position  between  wedges; 

it  is  removed  for  repairs,  or 
raised,  through  a  cover  plate 
on  the  side  of  the  tub,  just 
above  the  juncture  of  the  two 
halves  of  the  tub  casting.  The 
lighter  mechanism,  unlike  the 
Hollander,  does  not  have  a 
lever,  but  consists  of  an  L,  or 
boot-shaped  support  T,  Fig.  5, 
with  the  roll-bearing  box  B 
resting  on  the  horizontal  part 
(toe)  of  the  boot.  The  ver- 
tical part  may  end  in  the  form 
of  a  screw  running  in  a  composition-metal  nut  at  the  top.  This 
nut  is  geared  to  a  hand-wheel  shaft,  extending  across  the  tub,  by 
means  of  which,  both  ends  of  the  roll  spindle  are  adjusted  exactly 
and  together,  similar  to  the  hand-wheel  mechanism  of  the 
Hollander.  This  mechanism  is  housed  in  a  casting,  also  L- 
shaped,  which  rests  on  a  bracket  cast  on  the  side  of  the  tub;  it  is 
provided  with  a  locknut  adjustment,  by  means  of  which  the 
roll  may  be  alined  horizontally.  In  Fig.  5,  a  variation  of  this 
arrangement  is  shown.     Here  the  vertical  leg  E  has  a  heel  H 


Fig.  5. 


§3      BEATER  CONSTRUCTION  AND  OPERATION       13 

resting  in  a  socket,  and  is  connected  at  the  top,  by  a  pin  joint, 
to  a  casting  F.  The  latter  is  drilled  and  tapped  (threaded)  to 
take  the  screw  M,  which  has  bevel  gear  Gi  at  the  other  end,  and 
which  is  driven  by  G2  on  hand-wheel  shaft  N.  Any  movement 
of  M  will  pull  or  push  the  top  of  E,  which  is  the  long  arm  of  a 
bell-crank  lever,  and  thus  raise  or  lower  the  roll-bearing  box  B. 
A  stop  screw  S  fixes  the  lowest  position  of  5;  it  can  be  adjusted 
to  meet  the  conditions  of  stock  and  the  wearing  of  bars. 

18.  The  Miller  Duplex  Beater. — Inventors  have  endeavored 
many  times  to  increase  the  amount  of  roll  action  possible  during 
one  circuit  of  the  stock  around  the  tub.  Engineers  have  fre- 
quently tried  to  compute  the  effective  work  done  by  the  roll  on 
the  stock,  by  multiplying  the  number  of  bars  in  the  roll  by  the 
number  of  knives  in  the  bed-plate,  and  multiplying  this  product 


Fig.  6. 

by  the  number  of  revolutions  per  minute  of  the  roll,  the  final 
product  being  the  total  number  of  cuts  per  minute.  However, 
a  large  part  of  the  power  used  in  driving  the  ordinary  type  of 
beater  is  required  to  propel  the  stock  around  the  tub,  and  only 
a  smaU  proportion  is  required  to  overcome  the  friction  of  contact 
between  the  roll  and  the  bed-plate;  therefore,  it  is  urged  that 
more  cutting  action  in  the  same  capacity  of  tub  will  result  in  a 
more  efficient  beater. 

A  recent  application  of  the  foregoing  reasoning  is  embodied  in 
the  Miller  duplex  beater,  which  is  shown  in  Fig.  6.  Its  opera- 
tion is  similar  in  principle  to  that  of  the  Umpherston,  except  that 
a  second  bed-plate  is  placed  above  the  roll.  The  lower  bed-plate 
Pi  is,  of  course,  fixed  in  position,  while  the  hghter  mechanism,  in 
addition  to  carrying  the  roll  itself,  also  carries  the  upper  plate  P^. 
The  adjusting  device  that  raises  and  lowers  the  roll  is  so  designed 
as  to  move  the  upper  plate  Pi  exactly  twice  as  far;  thus  the 
distance  between  the  roll  and  the  lower  plate  is  always  equal  to 
the  distance  between  the  roll  and  the  upper  plate.     Springs  are 


14 


BEATING  AND  REFINING 


§3 


used  to  take  up  any  shock  on  the  upper  plate  in  case  of  hard 
objects  passing  through.  The  dumping  valve  D  is  similar  to 
that  of  the  Umpherston. 

19.  The  Marx  Beater. — The  Marx  beater,  shown  in  Fig.  7, 
is  in  line  with  the  effort  to  obtain  more  roll  action  for  the  same 
capacity  of  tub.     Here,  however,  there  are  two  complete  sets 


Fig.  7. 


of  roll  and  bed-plate,  each  with  its  own  hghter  equipment;  and 
to  accommodate  them,  the  tub  is  designed  in  the  form  of  a 
circuit  channel,  the  midfeather  being  changed  into  an  enclosure 
for  the  inboard  lighter  sets  and  pulleys.  An  advantage  derived 
from  this  design  is  that  one  set  of  roll  and  bed-plate  can  be 
made  of  one  type  and  the  other  set  of  another  type,  thus  produc- 
ing two  separate  kinds  of  action  on  the  stock  in  a  single  circuit 
around  the  tub.  In  Fig.  7,  roll  Ri  is  a  stone  roll,  while  roll  R2 
has  metal  bars. 


§3      BEATER  CONSTRUCTION  AND  OPERATION       15 

The  lighter  equipment,  shown  in  detail  at  (6),  Fig.  7,  embodies 
a  refinement  in  the  adjustment  of  the  roll,  which  is  effected  by 
a  lever  A  and  counterpoise  TF.  By  sliding  the  weight  W  outward 
on  the  lever,  more  of  the  weight  of  the  roll  can  be  counterbalanced, 
thus  leaving  less  of  its  weight  to  act  on  the  stock.  It  is  to  be 
noted  that  in  duplicating  the  roll  and  bed-plate,  it  is  also  neces- 
sary to  duplicate  the  dumping  outlet  0,  because  there  are  two 
low  places  in  the  bottom  of  the  tub,  one  in  front  of  each  roll. 


Fig.  8. 


The  roll,  if  made  of  stone,  may  be  turned  from  a  sohd  block 
and  scored  to  form  bars;  or  wedges  may  be  set  in  special  disks 
or  headers.  The  selection  of  the  stone  is  very  important.  Basalt 
lava  is  often  best;  it  has  small  cavities,  whose  edges  cut  and  do  not 
crumble. 

20.  The  Rabus  Beater. — The  Rabus  beater,  shown  in  Fig.  8,  is 
similar  in  arrangement  to  the  Home  beater.  The  tub,  however, 
is  modified  into  the  form  of  a  closed  circuit,  with  open  mid- 
feather,  in  the  effort  to  obtain  more  rapid  circulation  of  the  stock 


16 


BEATING  AND  REFINING 


with  the  same  expenditure  of  power.  The  channel  is  deeper,  and 
is  shaped  to  facihtate  the  flow  of  stock  and  prevent  lodging. 
Note  that  the  stock  flows  in  a  direction  opposite  to  that  in  the 
Home  beater,  Fig.  3. 

21.  The  Niagara  Beater. — A  very  recent  design,  which  has  met 
with  great  success  on  many  grades  of  paper  in  reducing  the  power 


Fig.  9. 


expenditure  in  beating,  the  time  required,  and  the  floor  space, 
as  compared  with  the  Hollander,  is  the  Niagara  beater,  shown  in 
Fig.  9.  Great  attention  has  here  been  paid  to  the  design  of  the 
channels  through  which  the  stock  must  circulate.  A  U-shaped 
bottom  and  a  very  high  back-fall  are  employed;  and  there  is  a 


§3      BEATER  CONSTRUCTION  AND  OPERATION       17 

marked  difference  between  the  width  of  the  channel  at  the  front 
side  and  at  the  roll  side  of  the  tub.  Although  the  roll  is  not 
submerged,  it  has,  nevertheless,  the  effect  of  being  submerged, 
by  reason  of  the  great  height  to  which  it  throws  the  stock  over 
the  back-fall,  K.  The  marked  reduction  in  time  required  for 
beating  with  this  beater  is  attributed  to  the  improved  circulation 
of  the  stock,  which  not  only  allows  the  roll  to  treat  the  same 
portion  of  the  stock  more  frequently  but  also  renders  a  con- 
siderable portion  of  the  power  used  in  circulation  available 
for  mechanical  work  by  the  roll  and  bed-plate  on  the  stock ;  and 
this  is  accomplished  with  an  unusually  high  consistency  of  stock. 

22.  The  Emerson  Beater. — Another  method  of  obviating  the 
tendency  of  the  stock  that  lies  next  to  the  midfeather  to  remain 
there  is  the  device  employed  in  the  Emerson  beater.  The 
midfeather  is  made  in  two  parts,  exactly  alike,  set  parallel  to  each 
other  in  one  tub,  with  space  enough  between  them  to  place  the 
roll.  The  roll  is  mounted  on  a  spindle  that  spans  the  entire  tub, 
as  in  the  case  of  the  Hollander,  with  the  lighter  equipment 
standing  outside  of  the  tub.  Thus,  the  stock  passes  under  the 
roll  in  this  central  channel,  over  the  back-fall;  it  is  divided  at 
the  rear  end  of  the  two  midfeathers,  one  half  passing  to  the 
right  and  the  other  half  to  the  left,  in  two  separate  channels,  to 
the  front  of  the  engine,  where  the  two  streams  reunite  in  the 
central  channel  and  again  approach  the  roll.  In  the  Emerson 
beater,  the  tub  is  more  nearly  oblong  in  plan. 

23.  The  Stobie  Beater. — Probably  the  modern  development  of 
short-fibered  chemical  and  mechanical  wood  pulps  has  brought 
forth  no  more  bold  departure  from  precedent,  in  the  matter  of 
design,  than  the  Stobie  beater.  This  apparatus  could  not  be 
employed  on  long-fibered  stocks,  but  it  applies  admirably  to  such 
materials  as  sulphite,  kraft,  soda  and  groundwood  fibers. 

An  open-tub  beater  is  used  as  a  container  in  which  to  mix  the 
ingredients  of  the  furnish,  and  to  break  up  the  laps  and  dry  broke  ^ 
that  may  be  used.  The  mass  is  then  dropped  into  a  chest,  which 
is  provided  with  a  good  agitator.  Drawing  from  the  bottom  of 
this  chest  is  a  three-stage  centrifugal  pump,  which  is  capable  of 

'  Broke  is  paper  that  has  been  discarded  anywhere  in  the  process  of 
manufacture.  Wet  broke  is  paper  taken  off  a  wet  press  of  a  paper  machine; 
dry  broke  is  made  when  paper  is  spoiled  in  going  over  the  dryers  or  through 
the  calenders,  trimmed  off  in  the  rewinding  of  rolls,  or  trimmed  from 
sheets  being  prepared  for  shipping. 


18  BEATING  AND  REFINING  §3 

delivering  the  stock  above  the  top  of  the  chest  to  three  or  four 
fire  nozzles,  arranged  in  a  battery  and  shooting  horizontally, 
at  a  pressure  of  about  75  pounds  per  square  inch.  Before  them 
is  arranged  a  plate,  the  surface  of  which  is  serrated  (something 
like  the  tread  of  an  iron  stair),  and  which  is  set  at  an  angle  that 
will  deflect  the  stock  downward  again  into  the  chest.  In  this 
manner,  the  stock  is  circulated  from  chest  to  pump,  to  nozzles, 
to  plate  and  back  to  chest  for  a  given  period  of  time.  It  is  then 
dehvered  to  the  paper-machine  chest  without  any  further 
refining.  Stock  at  a  consistenc\'^  of  2.5  %  is  circulated  for  a  period 
of  20  minutes,  the  nozzles  acting  under  a  pressure  of  75  pounds 
per  square  inch,  the  serrated  plate  being  set  at  an  angle  of  about 
45  degrees.  These  conditions  are  roughly  the  average  for  a 
hard  all-sulphite  paper. 

In  power  requirements,  the  pump  is  about  equivalent  to  a 
large  Jordan  engine;  and  there  is  also  to  be  added  the  power 
required  to  drive  the  breaking  engine,  in  which,  however,  it  is 
not  always  necessary  to  set  down  the  roll.  On  rough  computa- 
tion, the  Stobie  beater  would  require  about  120  horsepower-hours 
per  ton  of  paper  on  a  grade  that  would  require  about  370  horse- 
power-hours per  ton  of  paper  when  beaten  according  to  the  usual 
methods;  this  represents  a  power  saving  of  about  67%. 

24.  Besides  the  saving  in  power,  Stobie's  process  affords  the 
opportunity  of  gaining  close  control.  Once  the  consistency  has 
been  governed,  there  are  only  four  other  variable  factors:  the 
pressure;  the  character  of  the  plates;  the  angle  at  which  the  plates 
are  set;  and  the  length  of  time  of  beating.  The  character  of 
the  plate  and  the  angle  at  which  it  is  set  may  be  fixed 
mechanically,  and  a  recording  pressure  gauge  will  show  both  the 
pressure  and  the  time.  If,  then,  the  management  specifies 
what  nozzle  pressure  to  use  and  for  what  length  of  time  the 
process  must  run  on  each  furnish  of  stock,  there  is  practically 
absolute  control,  with  consequent  uniformity  of  results,  the 
only  remaining  condition  that  may  vary  being  the  characteristics 
of  the  raw  stock.  An  accurately  conducted  beating  process, 
however,  tends  to  reveal  such  changes  in  the  raw  stock  as  may 
occur,  and  the  management  has  the  best  opportunity  to  compen- 
sate for  these,  by  making  proper  changes  in  the  instructions 
governing  the  pressure  and  the  length  of  time.  In  this  way, 
it  is  possible  for  one  good  man  on  each  tour  to  attend  to  all  of 
the  beating  for  a  very  large  mill. 


§3      BEATER  CONSTRUCTION  AND  OPERATION       10 

To  just  what  extent  this  apparatus  will  apply  to  different 
classes  of  short-fibered  stock  and  to  different  requirements  as  to 
finished  paper,  remains  to  be  seen  when  mills  in  other  lines  of  the 
industry  are  permitted  to  experiment  with  it.  Certainly  the 
elements  of  which  the  Stobie  beater  are  composed,  are  capable 
of  great  modification,  to  suit  different  conditions;  and  this 
beater  therefore  represents,  perhaps,  the  most  hopeful,  as  well  as 
the  most  radical  development  in  beating  equipment  to  date. 


CARE  OF  BEATERS 

26.  Necessity  for  Exercising  Care. — The  very  simplicity  of 
the  design  and  construction  of  most  types  of  beaters  tends  to 
promote  laxity  in  caring  for  them.  This  is  particularly  true  in 
mills  making  coarse  boards  or  saturating  felts;  and  it  applies 
also  to  mills  using  waste  paper  and  cheap  pulps,  where  the 
beater  acts  largely  as  a  mixing  vat  and  the  roll  is  not  lowered  to 
any  extent.  But  it  is  in  mills  making  fine  papers,  where  the 
beaters  are  carefully  handled,  that  particular  attention  must  be 
paid  to  the  condition  of  the  fly-bars  and  bed-plate,  the  adjust- 
ment of  the  deflector  in  the  curb,  cleanliness,  power  con- 
sumption, and  the  condition  of  the  roll-adjusting  mechanism  and 
bearings. 

26.  Grinding  of  the  Roll  Bars. — During  beating,  the  fly-bars 
of  the  roll  and  the  knives  of  the  bed-plate  become  worn,  and  thoy 
must  be  replaced  from  time  to  time.  It  has  been  shown  that  the 
bars  may  easily  be  removed  from  the  roll;  also  that  the  bed-plate 
may  be  taken  from  the  beater  by  removing  a  plate  on  the  side  of 
the  tub,  taking  out  the  wedges  holding  the  chair  or  box,  and 
sliding  the  plate  out.  It  is  sometimes  possible  to  continue  to  use 
a  worn  roll  and  plate  by  chipping  out  some  of  the  wood  between 
the  bars,  and  thus  have  pockets  deep  enough  between  them  to 
produce  the  necessary  circulation, 

27.  After  the  roll  has  been  filled,  it  is  necessary  to  grind  it  to  a 
true  fit  with  its  bed-plate;  and  the  grinding  must  be  done  in  such 
a  manner  as  to  insure  that  all  bars  come  into  contact  throughout 
their  entire  length.  The  old  way  of  doing  this,  which  is  still  to 
be  preferred  where  the  finest  beating  is  to  be  done,  is  to  place  in 
the  tub,  in  front  of  and  behind  the  roll,  suitable  dams.     The 


20  BEATING  AND  REFINING  §3 

space  between  the  roll  and  the  dam  is  filled  with  fine,  sharp 
sand,  and  the  roll  is  turned  against  the  bed-plate  in  this  fine  sand 
until  the  sound  it  makes  and  an  inspection  of  the  bars  indicate 
a  perfect  fit.  During  this  operation,  enough  water  must  be 
added  periodically  to  prevent  the  development  of  too  much  heat. 

A  quicker  method,  but  not  so  satisfactory  for  fine  beating,  is 
to  remove  the  roll,  mount  it  in  a  lathe,  and  bring  the  bars  to  their 
proper  form  by  means  of  a  grinding  wheel.  The  bed-plate  is 
then  placed  under  a  grinding  wheel,  which  swings  over  a  radius 
equal  to  that  of  the  roll  with  which  it  is  to  run.  In  practice, 
this  method  is  available  only  to  the  larger  mills,  because  in 
smaller  mills  it  is  costly  to  remove  the  roll  from  the  beater  for 
refilling.  It  is  generally  desirable  to  grind  a  new  roll  also,  except 
where  it  is  to  be  used  for  coarse  boards  or  felts. 

In  addition  to  the  wearing  down  of  the  bars  during  beating, 
there  is  a  change  in  the  degree  of  sharpness  or  dullness  of  the 
bars,  which  is  a  very  important  factor  in  many  classes  of 
paper.  Blotting  paper  requires  sharp  bars,  whereas  glassine 
and  high-grade  bond  and  ledger  papers  require  dull  edges  on 
the  bars. 

28.  Cleanliness. — In  mills  making  white  or  colored  papers,  it 
is  of  importance  that  the  equipment  should  be  periodically 
washed,  to  remove  dirt  and  other  material  that  would  show  up  in 
the  finished  paper.  When  running  colored  papers,  the  coloring 
is  commonly  done  in  the  beater;  and  to  the  beaterman  falls  the 
task  of  seeing  to  it  that  every  beater  is  washed  free  from  stock 
carrying  any  color,  before  furnishing  stock  for  a  different  color. 
This  precaution  is  not  restricted  solelj''  to  the  beater,  but  applies 
also  to  all  the  equipment  through  which  the  stock  passes — head 
boxes,  spouts,  chests,  pumps  and  refining  engines.  Moreover, 
beating  equipment  ought  never  to  be  shut  down  for  more  than  a 
day  without  thoroughly  washing  out  every  part  of  it.  The 
stock  that  adheres  to  the  beater  becomes  very  hard  on  drying, 
does  not  readily  recover  its  water,  and  comes  off  in  lumps,  which 
will  reach  the  paper  machine  wire  to  some  extent  and  cause 
trouble  and  lumps  in  the  paper.  The  fine-paper  mills  have  a 
complete  wash-up  of  the  entire  beating  equipment  at  frequent 
intervals,  regardless  of  any  shutdown  or  change  of  color.  In 
some  cases,  the  spouts  are  constructed  entirelj'^  of  copper,  with 
many  hand  holes;  the  chests- are  surfaced  with  the  best  glazed  tile 
lining  and  all  inner  surfaces  are  kept  clean.     Sand  traps  and 


§3      BEATER  CONSTRUCTION  AND  OPERATION       21 

pockets  of  all  kinds  should  frequently  be  cleaned,  to  remove 
heavy  particles  of  dirt  and  metal. 

29.  Use  of  Paint. — When  the  parts  of  wooden  tub  Hollander 
beaters  are  delivered  by  the  builders  to  the  mill,  the  metal  parts 
are  coated  with  white  lead,  and  the  wood  parts,  including  the 
filling  strips  between  the  roll  bars,  are  heavily  primed  with  oil 
and  white  lead,  for  the  purpose  of  preventing  rust  of  the  metal 
parts  and  the  shrinking  or  checking  of  the  wood  parts.  The  out- 
side of  tub  and  curb  are  commonly  finished  with  shellac  and 
spar  varnish;  the  inside  of  the  tub  may  be  finished  with  oil.  In 
fine  mills,  during  the  periodic  shutdown  for  cleaning,  say  once  a 
year,  the  inside  surfaces  of  the  beater,  including  both  roll  and  bed- 
plate, are  both  thoroughly  scoured  free  of  the  thin  film  of  slime 
that  collects  from  the  stock;  and  the  end  spiders,  or  heads,  of  the 
beater  roll  are  thoroughly  scraped,  to  remove  slime  and  rust,  and 
are  coated  with  red  lead  or  some  other  anti-corrosion  paint.  It  is 
claimed  that  aluminum  bronze,  properly  applied,  gives  excellent 
service.  Where  cleanliness  is  of  prime  importance,  it  is  generally 
the  custom  not  to  allow  the  stock  to  come  in  contact  with  wood 
or  with  a  corrosive  metal  at  any  time ;  and  in  these  cases,  the  wooden 
tub  is  lined  with  a  non-corrosive  sheet  metal  (copper),  brazed  at 
the  joints,  and  roll  and  bed-plate  are  equipped  with  bronze  bars. 
The  roll  heads  are  cast  in  bronze,  or  if  cast  in  iron,  they  are 
sheathed  as  is  the  wooden  tub.  To  make  clean  paper,  the  beater 
room  must  be  kept  clean,  and  the  beaters,  chests,  etc.  thoroughly 
cleaned  periodically. 

30.  Swelling  of  Wood. — The  tightness  of  the  wood  tub,  and 
the  accuracy  of  form  of  the  beater  roll,  depend  upon  the  swelling 
of  the  wood  due  to  moisture.  It  is  the  swelhng  of  the  wood  strips 
between  beater  roll  bars  that  holds  the  bars  fast.  This  swelling 
must  have  taken  place  before  the  roll  is  finally  ground ;  for,  how- 
ever accurate  the  roll  may  be  when  dry,  it  will  be  thrown  out  of 
round  when  the  wood  strips  are  swelled.  Moreover,  a  roll  once 
put  into  service  and  ground  to  fit  its  bed-plate,  cannot  be  allowed 
to  dry;  because,  on  putting  it  back  into  service,  although  the  wood 
strips  will  swell  again,  they  will  not  restore  the  roll  to  its  former 
shape.  If  allowed  to  dry,  it  would  be  found  seriously  out  of 
round  and  would  have  to  be  reground.  Accordingly,  a  beater 
when  shut  down  must  have  water  in  it,  and  the  roll  must  be  turned 
over  once  or  twice  each  day  to  keep  it  in  shape. 


22  BEATING  AND  REFINING  §3 

BEATER-ROOM  EQUIPMENT 


CHESTS  AND  PUMPS 

31.  Other  Equipment  Necessary. — In  the  preparation  and 
supply  of  stock  or  stuff  to  the  paper  machine,  there  are  several 
different  types  of  equipment  necessary  besides  the  beaters.  Since 
the  beater  has  to  be  alternately  filled  (furnished)  and  discharged 
(dumped),  which  is  an  intermittent  process  known  as  the  batch 
process,  and  since  the  paper  machine,  on  the  other  hand,  draws 
stock  continuously,  there  must  be  in  practically  every  installation, 
several  beaters  feeding  a  single  paper  machine.  The  intermittent 
supply  of  stuff  from  the  beater  is  converted  into  a  continuous 
supply  through  storage  tanks  (chests)  and  pumps.  Gravity  is 
taken  advantage  of  wherever  possible;  but  in  practically  all 
mills,  stuff  pumps  are  used  for  forcing  the  stock  from  the  chests 
to  the  refining  engine  or  to  the  paper  machine.  In  addition  to 
the  above,  there  are  auxiliary  apparatus  of  various  kinds,  which 
are  used  in  connection  with  beaters,  or  are  used  for  regulating 
the  flow  of  stock. 

32.  Mixing  Chest. — Mills  making  low  grades  of  paper,  as 
for  example  news,  use  their  beaters  for  scarcely  any  other  purpose 
than  to  break  up  the  laps  of  stock  or  to  pulp  the  dry  broke. 
They  usually  depend  on  the  refining  engine  to  prepare  the  stock 
for  felting  on  the  paper-machine  wire.  In  some  cases,  the  stock 
comes  from  the  pulp  mill  in  slush  form,  and  is  mixed  in  a  tank  or 
chest  before  being  pumped  to  the  refining  engine.  One  form  of 
such  a  mixing  chest  is  shown  in  Fig.  10.  The  peculiar  feature 
of  this  chest  is  the  cyhndrical  coffer  A,  placed  inside  and  rigidh^ 
supported  from  the  walls  of  the  chest.  The  agitator  B  is  driven  at 
a  high  speed,  and  is  designed  to  propel  the  stock  downwards. 
The  bottom  of  the  chest  is  deeply  dished.  Thus  the  stock  receives 
more  or  less  violent  agitation  and  a  thorough  mixing.  The 
stock  outlet  is  at  0,  and  the  washout  is  at  W. 

33.  Stuff  Chests. — Stuff  chests,  shown  at  E  and  J,  Fig.  20, 
are  built  in  manj^  different  ways.  The  early  designs  were  the 
same  as  an  ordinary  water  tank,  cylindrical  in  form,  and  made  up 
of  two  heads,  and  with  straight  planks  and  staves,  held  tight  to 
the  circumference  of  the  heads  by  iron  hoops.  Although  this 
kind  of  chest  is  still  very  often  found,  it  is  being  replaced  by  more 


§3      BEATER  CONSTRUCTION  AND  OPERATION       23 

carefully  designed  chests;  partly  because  chests  of  larger  capacity 
are  now  demanded  in  mills  of  large  production,  and  partly 
because  the  different  character  of  modern  paper  stock  requires 
somewhat  closer  attention  to  the  design  of  chests  and  to  the 
materials  of  which  they  are  constructed. 


1 


Ll&f 


Fig.  10. 


34.  A  very  good  type  of  stuff  chest  is  shown  in  Fig.  11.  This 
is  a  so-called  vertical  chest,  built  in  cylindrical  form,  of  concrete 
or  brick,  and  lined  inside  with  glazed  tile.  To  set  the  tile  lining 
properly  requires  the  highest  degree  of  skill  on  the  part  of  the 
mason ;  because  the  surface  has  to  be  accurately  smooth,  and  all  the 
joints  must  be  perfectly  pointed  with  cement.  In  mills  using  a 
great  deal  of  clay  in  the  stock,  this  feature  is  especially  important. 
The  base  of  the  chest  has  a  fillet  on  the  inside,  to  prevent  the 


24 


BEATING  AND  REFINING 


§3 


lodging  of  dead  stock  at  the  juncture  of  side  wall  and  bottom;  and 
the  bottom  itself  is  dished  instead  of  being  flat.  Both  the  service 
outlet  and  the  sewer  outlet  are  placed  near  the  center  of  the  dished 


Fig.  11. 


bottom,  so  all  the  stock  can  be  run  out  when  changing  orders, 
changing  colors  or  shutting  down.  Similar  chests  are  often 
made  of  wood  preferably,  cypress. 


§3      BEATER  CONSTRUCTION  AND  OPERATION       25 

A  vertical  shaft  A,  whose  center  Hne  coincides  with  the  center 
Hne  of  the  chest,  turns  in  a  step  bearing  L,  usually  made  of 
lignum  vitse  and  set  in  the  bottom  of  the  chest.  To  this  shaft  is 
attached  a  series  of  agitator  arms  B,  so  designed  as  to  throw  the 
stock  outward  and  upward  along  the  wall  of  the  chest.  At  a 
higher  point  on  the  shaft  A  is  another  set  of  arms  E,  designed  to 
throw  the  stock  downward  at  the  center.  Arms  E  are  in  use,  of 
course,  onh'  when  the  chest  is  filled  to  their  level  or  higher.  A 
cup  D  catches  the  excess  oil  that  falls  from  the  upper  bearing  of 
the  vertical  shaft. 

Supported  over  the  chest  on  a  bridge  tree  is  a  shaft  S  and  pulley 
P,  with  or  without  a  clutch  K,  which  drives  the  agitator  through 
a  cone  pinion  and  crown  gear  C.  For  a  chest  12  feet  in  diameter 
and  10  to  12  feet  deep,  an  agitator  of  this  type  should  be  driven 
at  about  27  r.p.m.,  and  will  require  from  6  to  8  h.p.  In  mills 
making  a  good  grade  of  paper,  it  is  verj--  important  to  have  the 
chest  well  covered,  as  a  guard  against  dirt.  Somewhere  in  the 
top,  however,  there  is  provided  a  peep  hole,  illuminated  with  an 
electric  lamp,  so  the  beaterman  on  the  floor  above  can  see  at  all 
times  how  full  the  chest  is,  and  whether  or  not  the  agitator  is 
running. 

35.  Horizontal  Chest. — The  vertical  chest  shown  in  Fig.  11,  is 
preferred  by  some  to  the  horizontal  chest  shown  in  Fig.  12,  but 


SecVion  A-A 


Fig.  12. 


the  latter  type  is  by  no  means  uncommon,  and  it  may  be  required 
when  there  is  but  little  head  room.  As  illustrated,  it  is  a  cylin- 
drical wooden  tank,  built  on  its  side.  The  same  type  is  also 
built  of  brick  or  concrete,  without  the  upper  part  being  arched 
over,  the  sides  being  carried  straight  up  from  the  level  of  the 
center  line  of  the  agitator  shaft.     The  agitator  shaft  S  is  hori- 


26 


BEATING  AND  REFINING 


§3 


zontal;  it  carries  arms  B  and  is  driven  from  the  outside.  T  is  a 
support  for  the  center  bearing.  It  is  claimed  that  the  horizontal 
chest  produces  more  uniform  and  quicker  mixing. 

36.  Packing  Gland. — Fig.  13,  shows  a  typical  packing  gland, 
in  which  the  agitator  shaft  runs;  it  is  adapted  to  either  vertical 
or  horizontal  stuff  chests,  and  prevents  leakage.  Such  a  gland 
is  used  in  vertical  chests  when  the  driving  gear  is  below  the  chest; 
otherwise,  the  bottom  of  the  agitator  shaft  is  usually  set  in  a  step 
bearing  in  the  bottom  of  the  chest. 


Tap  Bolts- 


Packing 


Shaft 


Woodserews 


^Bottom    of  vertical 

or  side  of  horizontal 

stuffchest 


Fig.  13. 

37.  Stuff  Pumps. — The  work  done  in  lifting  paper  stock 
from  a  lower  to  a  higher  elevation,  as  at  points  F  and  K  in  Fig.  20, 
requires  that  the  amount  of  stuff  delivered  per  minute  shall  not 
vary,  whether  the  pump  is  drawing  from  a  full  chest  or  from  one 
that  is  nearly  empty;  under  such  conditions,  the  plunger  pump 
is  used.  Each  stroke  of  a  plunger  pump — sometimes  called  a 
displacement  pwjip— admits  and  discharges  a  fixed  volume  of 
stuff.  Plunger  pumps  are  designated  as  single  (or  simplex), 
duplex,  or  triplex,  according  as  they  have  one,  two  or  three 
cylinders.  Pumps  of  various  types  are  described  in  an  article 
by  E.  F.  Doty,  Paper  Trade  Journal,  beginning  Jan.  4,  1922, 
and  Pulp  and  Paper  Magazine  of  Canada,  beginning  Jan.  5,  1922 
(see  also  Vol.  V). 

38.  A  duplex  plunger  pump  is  represented  in  Fig.  14.  It  is 
driven  through  pulley  P,  either  with  or  without  a  set  of  reducing 


§3      BEATER  CONSTRUCTION  AND  OPERATION       27 


gears,  according  as  the  duty  of  the  pump  is  low  or  high.  By- 
means  of  a  crank  and  connecting  rod  T,  a  long  plunger  K  is 
moved  up  and  down  in  the  cylinder  C,  one  on  each  side  of  the 
pulley.  As  the  plunger  rises,  it  leaves  a  partial  vacuum  behind 
it,  which  draws  the  stuff  into  the  cylinder  at  the  suction  (or 
intake)  end.  When  the 
plunger  reverses  its  move- 
ment and  begins  to  descend, 
it  closes  the  suction  valve  and 
forces  (discharges)  the  stuff 
in  the  cylinder  through  the 
delivery  (discharge)  outlet. 

39.  The  manner  in  which 
the  plunger  pump  works  is 
shown  in  detail  in  Fig.  15, 
which  represents  a  section 
through  the  cylinder  of  a 
simplex  pump.  The  plunger 
A  is  long  and  hollow^;   and 


Fig.  14. 


Fig.  15. 


when  in  its  lowest  position,  as  shown,  it  occupies  almost  the  entire 
volume  of  the  cylinder  D.  The  plunger  runs  through  a  packing 
gland  G  at  the  top  of  the  cjdinder.  Directly  below  the  cylinder 
is  a  hollow  ball  F,  which  acts  as  a  valve,  admitting  stuff  to  the 
cylinder  as  long  as  the  plunger  moves  upward.  As  the  plunger 
starts  to  rise  from  its  lowest  position,  it  reduces  the  pressure 
behind  it.  The  difference  in  pressure  on  the  top  and  the  bottom 
of  the  ball  causes  it  to  rise  from  its  seat,  and  causes  a  flow  of 


28  BEATING  AND  REFINING  §3 

stock  upward,  following  the  plunger.  When  the  down  stroke 
begins,  the  pressure  on  the  top  of  the  ball  is  greater  than  that 
beneath  it;  this  forces  the  valve  (ball)  to  its  seat,  which  prevents 
the  stuff  from  flowing  back  through  the  inlet  pipe.  As  the 
plunger  descends,  the  pressure  increases;  the  stuff  confined  in 
the  cylinder  must  go  somewhere,  or  the  plunger  must  stop,  or  the 
cylinder  must  burst;  so  the  stuff  flows  through  the  discharge 
connection  B,  lifts  the  discharge  valve  (ball)  E,  and  discharges 
through  a  pipe  connected  at  C;  this  action  continues  until  the 
plunger  has  reached  the  full  limit  of  its  down  stroke.  When 
the  plunger  again  begins  to  rise,  the  pressure  above  valve  (ball) 
E  is  greater  than  beneath  it;  this  causes  E  to  close  (fall  back  to  its 
seat),  and  keeps  the  stuff  from  flowing  back  from  C;  valve  F 
rises,  and  the  cycle  is  repeated.  Both  ball  valves  are  made 
accessible  by  handholes,  covered  by  plates  H,  which  are  held 
tight  against  gaskets. 

40.  Caution. — In  operating  a  plunger  pump,  always  keep  in 
mind  two  very  important  precautions:  first,  never  allow  it  to 
pump  against  a  closed  valve,  for,  otherwise,  something  must 
give  way  and  serious  damage  must  result;  second,  be  sure  that 
the  stuff  being  pumped  is  free  from  foreign  substances,  such  as 
small  pieces  of  wood  or  rubber  hose,  which  may  get  under  the 
balls  and  cause  the  ball  valves  to  leak. 


QUESTIONS 

(1)  (a)  What  were  the  early  methods  of  beating?  (b)  When  was  the 
beater  invented? 

(2)  What  processes  are  carried  out  that  are  incidental  to  beating? 

(3)  Suppose  the  roll  spindle,  Fig.  1,  to  rest  at  the  center  of  the  lighter  bar 
D;  if  the  rod  K  has  a  thread  of  j-in.  lead,  the  worm  gear  L  has  20  teeth,  and 
the  hand  wheel  M  is  given  one-sixth  of  a  turn,  how  far  is  the  roll  lifted  from 
the  bed-plate?  Ans.    yj,^  in. 

(4)  Explain  the  circulation  of  stock  in  the  beater. 

(5)  What  are  the  objections  to  steel  bars,  and  what  other  materials  are 
used  ? 

(6)  In  what  respects  do  the  Home  and  Umpherston  beaters  differ  from 
each  other  and  from  the  Hollander? 

(7)  Describe  a  type  of  beater  other  than  those  mentioned  in  the  last 
question,  and  give  its  advantages  and  its  disadvantages. 

(8)  Would  you  prefer  a  vertical  or  a  horizontal  stuff  chest,  and  why? 

(9)  (a)  Why  is  the  plunger  type  of  pump  well  suited  to  pumping  paper 
stock?     (6)  What  precautions  must  be  observed  in  operating  it? 


§3      BEATER  CONSTRUCTION  AND  OPERATION       29 


(10)  What  must  be  the  minimum  diameter  of  a  cylindrical  stuff  chest 
under  the  following  conditions?  It  is  to  hold  two  beaters  of  stock,  each  of 
which  is  to  dump  1200  lb.  of  bone-dry  stock,  mixed  with  sufficient  water 
to  make  its  consistency  3%  (see  Art.  69);  the  total  head  room  in  the  base- 
ment is  15  ft.  3  in.;  18  in.  must  be  left  under  the  bottom  of  the  chest  for 
piping,  and  the  stock  level  must  be  kept  at  least  18  in.  from  the  top  of  the 
chest;  the  bottom  of  the  chest  is  4  in.  thick,  and  the  weight  of  a  cubic  foot  of 
stock  may  be  taken  as  62.5  lb.  Ans.  12  ft.  4  in. 


AUXILIARY  APPARATUS 

41.  Regulating  Box,— The  stuff  pump  must  deliver  a  constant 
quantity,  equal  to  the  maximum  amount  of  stock  required  for 
the  machines.  Provision  must  be  made  for  times  when  less 
than  maximum  capacity  is  wanted. 
In  Fig.  16,  is  shown  in  detail  a  very 
simple  form  of  regulating  box,  which 
may  be  used  as  at  G,  Fig.  20.  This 
is  simply  a  wooden  box  A,  divided 
nearly  in  halves  by  a  partition  B. 
The  part  ah  is  cut  lower  than  the 
part  he,  and  the  opening  thus  left  is 
provided  with  a  gate  G,  which  can 
be  adjusted  by  means  of  screw  S,  to 
close  all  or  a  part  of  the  opening. 
The  top  of  the  gate  G  may  be  raised 
higher  than  the  partition  at  he.  The 
partition  D  is  higher  than  he,  but 
lower  than  the  top  of  the  box.  When 
more  stock  is  pumped  into  the  box  at 
E  than  is  wanted  in  the  Jordan  (or 
the  paper  machine),  the  gate  is  raised 
until  the  excess  stock  passes  over  he 
into  compartment  7*^,  then  down  pipe 
H,   and  back  to  the   chest.     If  the 

stock  is  too  thick,  water  may  be  added  through  pipe  W.  There 
are  many  designs  of  regulating  boxes;  some  others  are  described 
in  the  Section  on  Paper-making  Maehines. 

Some  mills  even  have  consistency  regulators,  so  the  stock 
pumped  to  the  Jordan  regulating,  or  flow,  box  is  of  very  nearly 
constant  density.  A  complete  description  of  such  an  automatic 
regulating  device  may  be  found  in  Section  7,  page  57,  of  Vol.  Ill; 
it  is  briefly  described  in  this  Section  in  Art.  81. 


30 


BEATING  AND  REFINING 


§3 


42.  Washing  Cylinder. — It  is  sometimes  necessary  to  wash 
stock  in  the  beater;  or  to  increase  its  density  (thicken  it)  by 
removing  water.  This  is  done  commonly  by  means  of  a  washing 
cylinder,  such  as  that  described  in  Section  1,  Preparation  of  Rag 
and  Other  Fibers.  This  attachment  is  a  set  of  scoops  in  a  wire 
casing,  which  can  be  raised  and  lowered;  it  is  caused  to  rotate, 
so  as  to  dip  up  water  without  removing  fiber. 

43.  String  Catcher. — Fig.  17  represents  an  apphance  for  the 
open-tub  beater,  the  object  of  which  is  to  rid  the  stock  of  long 
strings,  such  as  may  be  found  in  various  classes  of  rag  and  rope 


Fig.  17. 

stocks.  The  string  catcher  is  mounted  in  the  tub,  in  front  of  the 
roll,  and  acts  in  the  same  manner  as  the  racks  at  the  inlet  of  a 
water  wheel.  The  arms  A  are  mounted  on  a  shaft  B  that  spans 
the  tub,  and  they  are  raised  by  means  of  a  hand  wheel  C,  geared 
to  a  quadrant  D.  The  arms  are  held  in  position,  when  down,  by 
a  pawl  E,  which  engages  with  a  ratchet  F,  which  is  on  the  same 
shaft  as  the  wheel.  The  lever  L,  attached  to  the  shaft  B,  carries 
a  weight  that  acts  as  a  counterbalance  to  the  arms  A . 

44.  Continuous    Beater  Attachments — Shartle  Attachment. — 

This  consists  of  a  casting  that  was  designed  to  replace  the  back- 
fall of  the  ordinary  Hollander  beater.  The  surface  toward  the 
roll  is  perforated,  and  means  are  provided  for  the  discharge  of 
stock  from  under  this  back-fall.  Assuming  that  the  object  of 
beating  is  to  reduce  the  stock  in  fineness,  or  length,  the  perfora- 
tions are  so  arranged  that  when  the  desired  fineness  has  been 


§3      BEATER  CONSTRUCTION  AND  OPERATION       31 

reached,  stock  will  begin  to  pass  the  holes  and  on  to  the  spout;  as 
fast  as  this  occurs,  fresh  stock  can  be  added  to  the  beater,  which 
is  thus  converted  from  a  batch  to  a  continuous  machine. 

45.  Bird  Attachment. — Similar  in  principle  to  the  Shartle,  is  the 
Bird  continuous  beater  attachment,  a  perforated  revolving  drum 
being  substituted  for  the  perforated  face  of  the  back-fall.  The 
drum  is  mounted  in  the  channel  of  the  tub  that  is  opposite  to 
that  of  the  beater  roll;  it  has  perforations  distributed  uniformly 
over  its  face  and  over  the  end  that  faces  the  midfeather.  The 
other  end  of  the  drum  is  open;  and  the  stock  that  flows  into  the 
drum  through  the  perforations  is  discharged  through  this  end 
into  a  spout,  which  extends  through  the  side  of  the  tub,  to  a  box 
outside  the  beater;  the  level  of  the  discharge  is  governed  by  an 
overflow  dam.  The  rate  of  discharge  is  governed  by  two  factors : 
The  size  of  the  perforations  relative  to  the  fiber-reducing  power 
of  roll  and  plate;  the  difference  in  level  between  the  stock  circu- 
lating in  the  tub  and  the  stock  discharging  from  the  spout.  As 
rapidly  as  the  stock  is  reduced  by  beating  and  discharged  through 
the  drum,  fresh  stock  is  added  to  the  beater,  thus  making  the 
process  a  continuous  one.  As  with  the  Shartle  attachment,  it 
is  assumed  that  the  stock  is  beaten  when  the  fibers  have  reached 
a  certain  fineness,  approximately,  and  these  attachments  work 
most  satisfactorily  when  this  assumption  is  substantially  correct ; 
they  are  best  suited  to  very  coarse  papers,  such  as  roofing  felts, 
leather  board,  and  the  like,  and  to  the  re-working  of  broke. 

46.  The  Griley-Unkle  Attachment.— The  Griley-Unkle  con- 
tinuous beating  attachment  is  also  based  on  the  assumption 
that  the  object  of  beating  is  to  reduce  the  paper  stuff  to  a  certain 
degree  of  fineness.  In  this  design,  the  perforated  plate  that 
separates  the  stock  is  located  in  the  hood,  or  curb,  of  the  beater, 
above  the  side  of  the  tub  and  on  the  front  side  of  the  beater  roll. 
The  perforations  are  kept  clear  by  means  of  a  series  of  plates, 
which  are  made  to  slide  over  the  perforations  (like  the  damper 
slides  of  a  cook  stove),  and  which  are  driven  by  the  action  of  a 
small  crank  that  is  belted  to  the  roll  spindle.  The  turning  of  the 
roll  throws  the  stock  off  by  centrifugal  force;  and  as  it  becomes 
fine  enough  to  pass  through  the  perforations  in  the  plate,  it  is 
collected  in  a  trough,  which  is  built  under  the  perforated  plate 
and  entirely  enclosed;  from  thence,  it  is  delivered  to  the  spouting 
system  below  the  floor,  through  its  own  down-spout.     A  stream 


32  BEATING  AND  REFINING  §3 

of  water  is  provided  in  the  collecting  spout,  to  thin  the  stock,  so 
it  will  flow  in  the  spouting  system.  The  field  of  application 
of  this  attachment  is  similar  to  that  of  the  two  previously 
mentioned. 

A  particular  application  of  this  device  is  in  the  reduction  of 
old  papers,  to  prepare  them  for  incorporation  in  the  sheet,  when 
this  can  be  done  without  the  direct  action  of  the  roll  on  the  bed- 
plate. If  the  slapping  of  the  roll  bars  is  relied  upon  to  break  up 
the  stock,  and  this  can  usually  be  done  in  substantially  the 
same  length  of  time  as  under  the  old  method  of  setting  the 
roll  down  to  working  position,  there  is  an  approximate  saving  of 
20%  in  power. 

47.  The  Roll  Counterpoise. — An  example  of  the  roll  counter- 
poise was  shown  in  connection  with  the  Marx  beater.  Fig.  7. 
A  graduated  arm  A  is  so  hung  that  it  gives  a  great  leverage  to 
the  weight  supported  near  one  end  of  the  hghter-bar  L.  The 
arm  A  is  a  lever  of  the  first  class,  the  power  arm  being  the  hori- 
zontal distance  from  o'  to  b',  and  the  weight  arm  is  the  horizontal 
distance  from  o'  to  a'.  Lighter-bar  L  is  a  lever  of  the  second  class, 
the  power  arm  being  the  horizontal  distance  from  o"  to  h",  and 
the  weight  arm  is  the  horizontal  distance  from  o"  to  a".  The 
whole  constitutes  a  compound  lever  having  a  velocity  ratio  of 

,  ,  ^ ,    „  „•  which  varies  with  the  position  of  the  weight  W  on 
0  a  X  0  a  '■ 

the  arm  A ;  and  more  or  less  of  the  weight  of  the  roll  can  thus  be 
counterbalanced.  With  the  weight  W  kept  in  a  particular  posi- 
tion, the  bearing  force  of  the  roll  on  the  bed-plate  is  constant. 
The  action  of  the  roll  on  the  stock  can,  of  course,  be  varied  by 
moving  the  weight. 

48.  The  Wallace -Masson  Beater-roll  Regulator. — With  a 
given  design  of  beater  and  a  given  type  of  filling  in  the  roll  and 
bed-plate,  an  effort  is  made  to  control  the  operation  of  the  beater 
by  so  governing  the  adjustments  of  the  roll  that  the  roll  will  exert 
a  given  pressure  on  the  bed-plate;  the  counterpoise  shown  in  Fig. 
7,  is  one  method  of  accomplishing  this.  Another  method  is  the 
Wallace-Masson  beater-roll  regulator,  shown  in  Fig.  18.  A 
frame  spans  the  entire  tub,  in  a  line  parallel  to  the  axis  of  the 
roll  spindle;  it  carries  two  pivot  bearings  T,  in  which  are  hung 
two  levers  F,  both  of  which  are  connected  to  the  piston  rod  in  the 
hydraulic  cylinder  C.    Levers  F  bear,  at  their  outer  ends,  on 


§3      BEATER  CONSTRUCTION  AND  OPERATION       33 


S 


...¥. 


iiz: 


aa 


top  of  the  lighter-bars  H.  The  latter  are  counterpoised  by  means 
of  levers  L  carrying  weights  W]  and  weights  W  are  made  suffi- 
ciently heavy  to  balance  the  entire  weight  of  the  roll,  spindle, 
lighter-bars,  and  bearings,  and  the  belt  pull  also,  if  it  be  down- 
wards. The  pressure  of  the  roll  on  the 
bed-plate  is  thus  independent  of  the 
weight  of  the  roll;  it  is  developed  by 
admitting  water,  under  pressure,  to  cyl- 
inder C,  through  admission  pipe  A,  and 
relieving  through  exhaust  pipe  E.  The 
exact  pressure  applied  to  the  stock  is 
thus  registered  by  the  pressure  gauge  D. 
By  making  D  a  recording  gauge,  a  record 
may  be  had  showing  exactly  what 
pressures  were  used  at  every  minute  of 
the  day;  and  it  will  also  serve  as  a  basis 
for  framing  the  instructions  for  beating. 
Since  the  roll  is  completely  counterpoised, 
the  bearing  is  provided  with  an  upper 
half,  or  top  bearing,  through  which  the 
force  necessary  to  produce  the  desired 
roll  pressure  must  be  transmitted. 

49.  The  Adjustable  Doctor.— In  the 
better  constructed  beaters,  the  doctor 
.  that  is  placed  at  the  back  side  of  the 
roll,  over  the  back-fall  is  adjustable. 
Those  in  charge  of  mills  should  watch 
the  rolls  carefully,  to  observe  whether 
stuff  is  being  thrown  over  from  the 
back  to  the  front;  if  so,  the  doctors 
should  be  adjusted  to  prevent  this  as 
much  as  is  possible.  While  no  great 
harm  results  from  this  carrying  over,  it 
tends  to  limit  the  capacity  of  the  beater 
by  reducing  the  speed  of  circulation  of 
the  stock.  When  adjusting  the  doctor, 
it  should  not  be  set  so  close  to  the  roll  that  ordinary  bumps  bring 
the  doctor  and  roll  into  contact. 

In  Fig.  19,  is  shown  Shlick's  beater-hood  attachment,  by 
which  the  Hollander  beater  maj'  be  so  modified  as  to  become  a 
new  type.     The  adjustable  doctor  D  is  connected  with  the  fighter- 


34 


BEATING  AND  REFINING 


§3 


bar  and  in  some  cases  to  the  roll  journal,  so  that  the  doctor  is 
raised  when  the  roll  jumps  or  is  brought  up  by  the  wheel. 

A  high,  deflecting  hood  or  curb  is  indicated  at  H  with  cor- 
respondingly high  back-fall,  which,  together  with  an  elongation 
of  the  midfeather  and  heightening  of  the  tub,  increases  the  circu- 
lation of  the  stock.  The  increased  height  of  the  back-fall  is  shown 
at  A  and  B.  Many  such  variations  are  being  developed  and 
experimented  with  at  the  present  time. 


Fig.  19. 


BEATER-ROOM  LAYOUT 

50.  Fundamental  Conditions. — It  is  probable  that  there  are 
no  two  beater  rooms  in  this  country  that  have  the  same  arrange- 
ment of  beaters,  chests,  refining  engines,  mixing  tanks,  etc.  The 
kinds  of  pulps  used,  the  form  and  manner  in  which  the  stock 
is  brought  to  the  beater  room,  the  method  of  beating,  the  design 
of  the  building  and  the  arrangements  of  the  other  parts  of  the 
mill,  changes  in  arrangement  or  rebuilding  of  old  mills,  power 
conditions,  size  of  the  paper  machines,  and  many  other  factors, 
affect  the  beater-room  layout.  In  general,  however,  there  are 
certain  fundamental  conditions  which  are  observed  and  which 
are  considered  when  designing  a  new  mill  or  rebuilding  an  old 
one.  The  distance  between  the  beaters  and  the  chests  should 
be  as  short  as  possible,  and  the  down  spouting  should  be  (as 
nearly  as  possible)  in  straight  lines  with  no  sharp  turns.  The 
pumps  should  be  close  to  the  chests,  and  the  stuff-boxes  and 


§3      BEATER  CONSTRUCTION  AND  OPERATION       35 

flow-boxes  should  be  close  to  the  pumps,  refining  engines,  and 
chests.  Long  drives  or  shafting  are  to  be  eliminated  wherever 
possible.  Two  beaters,  or  even  one,  to  one  paper  machine  are 
often  found  in  small  mills  or  in  mills  where  the  capacity  of  the 
paper  machine  is  not  large.  When  the  capacity  of  the  machine  is 
very  large  or  where  a  considerable  amount  of  beating  has  to  be 
done  on  each  furnish  of  stock,  the  number  of  beaters  to  one 
machine  may  be  as  large  as  eight.  In  general,  it  may  be  stated, 
that  good  design  calls  for  a  small  number  of  beaters  for  machines 
of  low  capacity  and  a  relatively  large  number  for  machines  of 
high  capacity. 

51.  Diagram  of  Layout. — For  the  purpose  of  illustrating  the 
general  relationships  of  the  various  pieces  of  equipment  in  the 


^ 


^ 


^ 


^^ 


E 


Fig.  20. 


beater  room,  a  layout  of  four  beaters,  two  chests,  flow-boxes, 
a  refining  engine,  and  pumps  is  shown  in  Fig.  20.  The  beaters 
A  are  arranged  in  a  straight  line,  and  the  dumping  valves  dis- 
charge into  vertical  down  spouts  JB,  which  lead  to  a  collecting 


36  BEATING  AND  REFINING  §3 

spout  C  that  runs  under  the  beater  floor,  almost  horizontally. 
The  spout  C  should  have  a  slight  pitch  in  both  directions  toward 
the  point  of  its  junction  with  the  single  down  spout  D,  which 
leads  to  the  chest  E.  In  the  operation  of  the  mill,  assuming 
that  fresh  stock  is  furnished  to  all  the  beaters,  they  would  be 
furnished  in  rotation,  and  would  be  dumped  in  rotation  also. 
The  stock  thus  passes  in  batches  to  the  stuff  chest  E,  which  is 
built  large  enough  to  hold  at  least  two  beaters  of  stock,  and 
which  acts  as  a  reservoir.  Leading  from  the  bottom  of  chest  E 
is  an  outlet,  through  which  the  stock  is  drawn  in  a  continuous 
stream  to  the  pump  F,  which  raises  the  stock  to  a  flow-box  G, 
placed  above  the  Jordan  refining  engine.  The  flow-box  is 
provided  with  a  regulating  device  and  an  overflow  pipe  L;  the 
latter  returns  to  the  chest  E  whatever  the  pump  F  throws  that  is 
in  excess  of  what  the  paper  machine  requires  to  pass  through 
the  refining  engine.  The  refining  engine  H,  which  will  be 
described  later,  discharges  in  a  continuous  stream  into  a  box  /, 
by  means  of  which  the  pressure  imposed  on  the  stock  while 
passing  through  the  refining  engine  can  be  governed;  and  from 
box  7,  the  stock  falls  to  the  second  stuff  chest  J.  This  last  is 
the  reservoir  from  which  the  paper  machine  drawls  its  supply, 
through  another  pump  K,  just  as  chest  E  is  the  reservoir  from 
which  the  refining  engine  H  draws  its  supplj-;  hence,  E  is  known 
as  the  Jordan  chest,  and  J  as  the  machine  chest.  In  many  instal- 
lations, box  I  is  not  included.  Both  of  the  chests  E  and  J  are 
provided  with  agitators  T. 

It  is  customary  to  place  the  beaters  in  pairs,  as  shown  in  the 
illustration,  with  pulleys  adjacent.  In  this  arrangement,  the 
drivers  are  least  in  the  way,  and  the  free  space  left  between 
beaters  may  be  made  sufficiently  wide  to  afford  trucking  way 
when  desired.  This  arrangement  permits  of  a  group  drive, 
though  the  beaters  may  be  driven  in  pairs  or  individually  by 
motors.  The  group  drive  tends  to  put  a  more  uniform  load  on 
the  motor,  when  a  motor  is  used  as  a  source  of  power.  Water 
wheels,  when  used  as  sources  of  power,  are  commonly  connected 
to  beaters  in  groups;  this  sometimes  necessitates  complicated 
belting  and  long  lines  of  shafting,  all  of  which  consumes  power 
and  involves  expense  for  maintenance. 


§3      BEATER  CONSTRUCTION  AND  OPERATION       37 

FURNISHING  THE  BEATER 

52.  Composition  of  the  Furnish. — The  mixture  of  the  various 
materials  that  are  blended  in  the  beater,  and  of  which  the  paper 
is  ultimately  composed,  is  called  the  furnish.  The  chief  con- 
stituent of  this  furnish  is,  of  course,  the  fibrous  material;  and 
to  this  may  be  added  rosin  size,  mineral  substances,  called 
loading  or  filler,  coloring  matter  and  alum  (aluminum  sulphate) 
in  varying  proportions,  sodium  silicate,  starch,  etc.,  as  required. 
The  kind  of  paper  to  be  made  determines  the  presence  or  absence 
of  one  or  more  of  these  non-fibrous  constituents  of  the  furnish, 
but  nearlj'-  every  paper  requires  the  use  of  alum.  The  operation 
of  filling  up  or  charging  the  beater  with  these  materials  is  called 
furnishing.  The  furnishing  must  be  carried  out  in  such  a 
manner  as  to  form  a  moving  mass  of  slush  throughout  the  process, 
which  must  provide  for  carrying  the  stock  under  the  roll.  It  is 
a  great  advantage  to  have  one  kind  of  stock  in  slush  or  wet  form, 
which  can  be  drawn  from  a  pipe  or  dug  from  a  stock  box,  so  that 
the  circulation  around  the  tub  will  begin  at  once.  Lacking 
this,  it  is  often  necessary  to  make  the  initial  slush  by  forcing  some 
pulp  under  the  roll  with  a  paddle,  after  a  small  quantity  of  water 
has  been  put  in;  water  alone  will  not  carry  dry  or  pressed  pulp 
under  the  roll. 

CONDITION  AND  HANDLING  OF  PULPS  OR  HALF-STUFF 

53.  Condition. — The  pulp  or  half-stuff,  the  fibrous  part  of  the 
furnish,  may  come  to  the  beater  room  in  many  forms:  dry 
or  wet  broke  from  the  paper  machine;  pulped  waste  paper  in  cars 
from  the  drainer  or  in  slush  form  from  storage  tanks;  wood  pulp 
in  dry  sheets,  in  rolls,  or  in  dry  or  semi-wet  laps;  wet  half-stuff 
in  cars  from  the  drainers;  or  various  pulps  in  slush  form  or  from 
thickeners.  The  handhng  of  the  stock  in  furnishing  is  as  varied 
as  is  the  beater-room  layout  and  the  form  in  which  pulp  reaches 
the  beater  room. 

54.  Pulping  Broke. — In  man}-  mills,  the  beating  equipment  is 
utilized  to  pulp  the  dry  waste  of  the  mill.  This  is  done  in  two 
different  ways:  (a)  One  or  two  beaters  of  the  set  are  used  exclu- 
sively as  broke  beaters,  a  small  quantit}^  of  broke  being  dropped 
into  the  chest  each  time  a  beater  of  fresh  stock  is  dumped;  or  (6) 
a  proportion  of  dry  paper  is  incorporated  with  each  furnish,  and 


38 


BEATING  AND  REFINING 


§3 


all  beaters  of  the  set  are  used  alike.  By  either  plan  certain 
beating  capacity  is  withdrawn  from  the  beating  of  fresh  stock. 
In  many  mills  some  independent  form  of  waste-paper  pulper 
is  preferred,  which  will  deliver,  for  the  furnish,  stock  that  has 
been  thoroughly  wetted  and  reduced  to  a  pulp.  One  type  of 
pulper  for  this  purpose  is  shown  in  Fig.  21. 

55.  This  pulper  consists  of  a  hopper  H,  Fig.  21,  mounted  on  a 
barrel  B,  the  axis  of  which  coincides  with  the  axis  of  a  shaft  that 
is  driven  by  a  strong  gear-reduction  set.  The  shaft  carries 
radial  arms  C — see  detail  at  (a) — which  turn  with  their  ends  very 
close  to  the  inside  of  the  barrel  B.  The  dry  paper  enters  the 
hopper  with  water  and,  usually,  with  steam  also.     The  mixture 


Fig.  21. 

is  driven  toward  the  barrel  by  a  worm-screw  conveyor,  under 
the  pressure  of  which,  it  is  forced  through  the  barrel  to  the 
counterweighted  discharge  door  D.  During  its  passage  through 
the  barrel,  it  is  worked  by  the  radial  arms  C.  These  arms  are 
cast  with  their  forward  face  in  the  form  of  a  cam,  which  tends  to 
pinch  the  stock  against  the  inside  of  the  barrel  and  the  pins  E  and 
to  roll  it  at  the  same  time.  The  result  is  a  moist  pulp,  which 
readily  mixes  with  the  other  stock,  when  furnished  to  the  beater. 
In  many  cases,  it  is  possible  to  withhold  this  disintegrated  paper 
from  the  beater  until  all  of  the  fresh  stock  has  been  beaten,  thus 
saving  very  greatly  in  beater  capacit}'^;  it  is  then  added  with 
enough  allowance  of  time  before  dumping  to  ensure  thorough 
mixing. 

Another  type  of  waste-paper  pulper,  also  used  for  mixing  wood 
pulp,  is  described  in  the  Section  on  Treatment  of  Waste  Papers. 
It  is  essentially  a  beater,  with  a  paddle  wheel  on  one  shaft  for 
circulating  stock,  making  about  14  r.p.m.  The  other  shaft  is 
set  with  thin  blades  and  makes  150  r.p.m.,  slushing  the  stock 
and  mixing  it. 


§3      BEATER  CONSTRUCTION  AND  OPERATION       39 

56.  Frozen  Pulp.— Frozen  laps  of  wood  pulp  are  a  source  of 
considerable  trouble  in  the  beater  room.  It  is  difficult  to  break 
up  such  laps  by  hand,  and  it  is  not  always  convenient  to  store 


FiQ.  22. 


them  mdoors  until  they  thaw;  while  to  thaw  them  with  steam  is 
expensive.  If  they  are  fed  direct  to  the  beater,  damage  may 
result.     To  facilitate  the  furnish  and  to  aid  the  beater  in  convert- 


40  BEATING  AND  REFINING  §3 

ing  the  laps  into  slush  of  the  proper  consistency,  the  use  of  a 
machine  is  advisable.  A  patented  shredder  that  is  widely  used 
for  this  purpose  is  illustrated  in  Fig.  22.  The  stock  is  fed  over 
the  feeding  table  A,  and  is  passed  on  by  corrugated  roll  B,  while 
it  is  torn  into  fragments  by  the  blades  C.  These  blades  have  a 
serrated  edge,  and  are  so  mounted  on  an  arbor  as  just  to  clear 
the  steel  shoulder  D,  which  is  mounted  on  the  edge  of  the  feeding 
table.  This  machine  is  rated  to  consume  less  than  30  h.p.  in  the 
preparation  of  5  tons  of  dry  stock  per  hour. 

57.  Slush  Pulps. — It  is  common  practice  in  news  mills,  and  in 
some  mills  making  higher  grades,  to  furnish  the  stock  in  slush 
form.  This  is  done  where  the  preparation  of  pulp  is  under  the 
same  management  as  the  paper  mill  and  the  pulp  mill  is  conven- 
iently located,  so  that  the  pulp  may  be  pumped  directly  to  the 
beater  or  fed  by  gravity  from  storage.  Stock  in  slush  form  is 
generally  mechanical  (i.e.,  groundwood),  sulphite  or  soda  pulp, 
or  pulped  waste  papers.  Where  more  than  one  slush  pulp  is 
furnished  to  a  single  beater,  separate  pumps  and  piping  are  used. 
It  is  customary  to  eliminate  some  of  the  water  from  these  pulps 
before  furnishing  them  to  the  beater  by  means  of  various  types 
of  thickeners,  as  explained  in  Section  7,  Vol.  III. 

58.  Dry  and  Semi-dry  Pulps  and  Half-stuff. — Practically  all 
other  pulps  or  stock  are  charged  or  furnished  into  the  beater  by 
hand.  Water  is  first  put  in  the  beater,  and  then  the  pulp  or 
half-stuff  is  added.  Laps  or  sheets  are  broken  up,  and  care  is 
taken  that  large  lumps  of  stock  are  not  permitted  to  go  under  the 
roll.  Half-stuff  is  dug  out  of  drainer  boxes  in  which  it  is  pushed 
to  the  beaters.  Dry  broke  is  added  slowly,  and  with  care  not  to 
jump  the  roll.  Pulp  in  rolls  is  generally  added  by  pulHng  out  the 
center  of  the  roll  and  pushing  the  end  of  the  continuous  sheet 
under  the  beater  roll.  The  roll  of  pulp  is  held  pointing  towards 
the  beater  roll,  which  pulls  the  pulp  in  a  continuous  sheet  from  the 
center  of  the  roll.  In  other  cases,  the  roll  may  be  run  on  a  piece 
of  pipe,  held  by  two  men,  or  in  a  frame. 


ORDER  OF  FURNISH 

59.  Usual  Order. — There  are  many  and  varying  ideas  regard- 
ing the  proper  order  for  furnishing  the  different  materials  to  the 
beater.  If^stock  is  available  in  slush  form,  it  should  go  in  first. 
If  the  stockis  so  thin  that  other  stock  added  in  the  form  of  drained, 


§3      BEATER  CONSTRUCTION  AND  OPERATION       41 

rag  half-stuff,  or  dry  pulp  will  not  give  the  desired  density,  the 
excess  of  water  is  removed  by  the  washer  while  the  furnishing 
proceeds;  then  lap  or  roll  pulp,  or  rags,  or  pulped  paper  is  put  in. 
Claj''  or  other  filler  is  usually  added  with  the  fiber  or  immediately 
after  it.  The  order  in  which  size,  alum,  and  color  are  added 
varies  with  conditions;  but,  as  a  rule,  the  size  is  added  early 
enough  to  allow  for  thorough  mixing,  and  to  have  the  effect  of  the 
size  on  the  colors  evident  before  the  coloring  has  developed. 
Then  the  color  is  added  and  is  well  distributed,  so  that  when  the 
alum  is  finally  put  in,  the  coloring  and  sizing  will  be  uniform 
throughout  the  mass.  Exceptions  to  this  order  will  be  mentioned 
in  the  Sections  treating  of  Coloring  and  Sizing. 

60.  Loading. — Mineral  loading,  or  filler,  is  included  in  the 
furnish  to  give  the  paper  opacity,  to  give  the  paper  a  smooth 
surface  or  finish,  to  assist  in  the  development  of  the  color 
(principally  in  white  papers),  and  in  some  cases,  to  increase  the 
weight  of  the  paper.  The  usual  loading  materials  are  clay, 
calcium  sulphate,  and  talc.  Clay  and  talc  can  be  added  to  the 
beaters  dry.  Clay  and  calcium  sulphate  (crown  filler)  reach  the 
mill  in  casks,  and  have  to  be  weighed  into  the  proper  batches 
for  adding  to  the  beater  furnish.  Clay  is  also  bought  in  bulk 
in  carload  lots.  Talc  comes  in  sacks  already  weighed.  If  clay  is 
used,  the  most  satisfactory  way  to  handle  it  is  to  mix  it  carefully 
with  water  in  proper  proportions,  have  a  tank  of  it  (which  acts  as 
a  reservoir)  mechanically  agitated,  and  draw  a  prescribed  volume 
of  this  clay  milk  into  the  beater  while  the  stock  is  traveling. 
Further  information  concerning  this  operation  is  given  in  the 
Section  on  Loading  and  Engine  Sizing. 

61.  Sizing. — The  treatment  of  stock  with  a  substance  that 
tends  to  make  the  paper  water-  or  ink-resisting  is  called  sizing. 
The  substance  usually,  almost  universally,  employed,  where  the 
sizing  is  done  in  the  beater,  is  a  soap  obtained  by  boiling  rosin 
with  soda  ash.  This  is  added  to  the  beater  either  by  using  dip- 
pers or  by  first  emulsifying  it  in  cold  water  and  then  adding  to  the 
beater  in  the  form  of  milk.  The  latter  method  is  finding  increas- 
ing favor,  largely  because  of  its  convenience,  and  also  because  of 
the  better  distribution  throughout  the  beater  that  can  be  obtained 
by  running  in  the  milk  while  the  stock  is  traveling.  The 
chemistry  of  sizing  is  very  complex,  and  it  is  not  thoroughly 
understood.     The  important  fact  for  the  beaterman  to  keep  in 


42  BEATING  AND  REFINING  §3 

mind  is  that  two  things  are  required  in  sizing:  first,  to  add  the 
size,  and  then  to  add  the  alum.  Adding  the  alum  (aluminum 
sulphate)  to  the  furnish  before  the  size  has  had  time  to  become 
intimately  mixed  in  all  parts  of  the  mass,  defeats  the  sizing  action. 
The  subject  is  more  fully  discussed  in  the  Section  on  Loading  and 
Engine  Sizing. 

62.  Coloring. — Adding  the  coloring  matters  is  a  part  of  the 
beaterman's  duties.  Here,  again,  the  chemistry  is  very  complex, 
and  is  still  little  understood,  in  some  respects.  Some  coloring 
materials  are  better  developed  h\  following  the  alum  than  by 
preceding  it  in  the  furnish.  More  of  the  common  paper-mill 
colors  are  better  developed  b}'  being  added  before  the  alum, 
while  with  some  it  makes  but  little  difference  which  is  added  first. 
However,  the  practical  way  of  running  a  mill  is  to  have  a  fixed 
rule,  one  that  is  nearest  right  on  the  average,  and  which  will  not 
involve  a  lot  of  men  in  the  complexities  of  chemistry.  With 
this  in  mind,  chemists  and  color  experts  seem  to  agree  that  the 
best  practice  is  to  add  the  size  early  in  the  run,  to  add  the  colors 
at  a  time  that  will  permit  of  thorough  distribution  and  develop- 
ment, and  to  add  the  alum  as  near  to  the  dumping  time  as  is 
possible.  The  fact  that  the  slight  excess  of  alum  that  is  always 
necessary  will  cause  sufficient  acidity  to  attack  the  steel  of  the 
roll  and  bed-plate  is  one  more  reason  for  this  order  of  adding 
these  materials. 

The  matter  of  matching  shades  and  choosing  coloring  materials 
involves  a  world  of  intricate  technology,  which  will  not  be 
discussed  here.  The  subject  of  coloring  is  treated  in  the  Section 
on  Coloring. 

TYPICAL  FURNISHES 

63.  Reasons  for  Variation. — In  order  that  the  student  maj- 
obtain  a  general  idea  of  some  of  the  principles  involved  in  the 
furnishing  and  beating  of  stock  for  certain  tj^pes  of  paper,  a  few 
illustrations  are  given.  It  must,  however,  be  kept  in  mind  that 
the  method  of  furnishing,  the  order  of  furnishing,  and  the  manipu- 
lation of  the  roll,  will  seldom  be  the  same  in  any  two  mills,  even 
on  the  same  type  or  kind  of  stock.  Experience  has  indicated 
certain  general  methods  of  procedure;  but  in  a  large  number  of 
mills,  furnishing  and  beating  are  not  under  close  technical  control, 
and  the  skill  and  experience  of  the  beaterman  is  relied  upon  to  a 


§3      BEATER  CONSTRUCTION  AND  OPERATION      43 

very  great  extent.  Variation  in  the  quality  or  character  of  the 
raw  materials  obtained  is  also  a  factor  that  makes  it  difficult 
to  maintain  the  same  formula  for  any  given  kind  of  paper.  There 
are,  therefore,  so  many  factors  which  affect  the  furnish  and  the 
actual  operation  of  beating,  that  the  examples  given  must  be 
considered  to  be  very  general. 

64.  High-grade  Rag  Bond. — Assuming  the  use  of  a  700-pound 
Hollander  beater,  half -stuff  from  number  one  "shirt  cuts" 
(a  high-grade  of  new,  white,  cotton  shirt  cuttings),  an  8-hour 
beating  for  a  high-grade,  all-rag  bond  paper,  and  engine  sizing 
sufficient  for  later  tub  sizing,  the  following  procedure  will  give 
an  indication  of  mill  practice.  Before  adding  any  stock,  or 
rather  before  dumping  the  previous  beater,  the  roll  is  raised  off 
the  plate  about  15  turns  of  the  hand- wheel.  This  is  necessary 
to  give  clearance  for  the  bunches  of  stock.  The  beater  is  first 
filled  about  half  full  of  water,  which  is  carefully  filtered,  or 
strained  through  a  cloth  bag  usually  made  of  press  felt.  The 
half -stuff  is  brought  up  from  the  drainer  room  in  "stock  boxes," 
containing  about  150  to  200  pounds  air-dry  fiber  which,  as  it 
comes  from  the  drainer,  contains  from  70%  to  75%  of  water. 
The  half-stuff  is  charged  into  the  beater  by  hand,  tongs,  or 
forks,  and  in  this  case  about  4^  boxes  of  stock  would  be 
used.  Water  is  gradually  added  as  the  half-stuff  fills  the 
beater.  When  completely  charged  with  half-stuff  and  water, 
the  concentration  or  density'  of  the  stock  will  be  between  4%  and 
5%.  The  stock  in  the  beater  is  very  lumpy  and  the  surface  is 
not  smooth. 

After  about  a  half  hour  of  circulation  of  the  stock,  the  roll  is 
lowered  5  turns.  At  each  succeeding  half  hour,  the  roll  is 
lowered  2  turns  until  it  is  2  turns  off  the  plate,  at  the  expiration 
of  2|  hours.  The  rosin  size  is  then  added,  (assuming  that  it  is  in 
milk  form)  from  a  measuring  tank;  70  gallons  of  size,  containing 
about  0.3  pounds  per  gallon  are  added,  equal  to  3  %  on  the  weight 
of  the  stock.  It  is  preferable  to  strain  this  size  while  adding  it. 
Strainers  can  be  made  by  putting  a  bottom  of  machine  wire  or 
press  felt  on  a  shallow  box  about  2  feet  square.  By  this  time,  the 
lumps  of  the  stock  have  begun  to  disappear  and  the  surface 
becomes  more  smooth.  The  roll  is  lowered  by  half  turns  each 
half  hour  until  it  is  one-half  turn  off  the  plate.  It  is  lowered  a 
quarter  turn  at  the  end  of  the  next  half  hour,  and  another  quarter 
turn  at  the  end  of  the  next  hour.     The  color,  dissolved  in  hot  or 


44  BEATING  AND  REFINING  §3 

cold  water  as  the  case  may  be,  and  strained,  is  added.  At  the 
end  of  6|  hours,  the  hand  wheel  is  turned  down  another  quarter 
turn,  leaving  the  full  weight  of  the  roll  on  the  stock.  About 
25  pounds  of  alum,  dissolved  in  hot  water  and  strained,  is  then 
added,  and  at  the  end  of  the  8-hour  period,  the  roll  is  raised 
15  turns,  the  valve  opened  and  the  stock  is  dumped  to  the  Jordan 
chest,  with  some  additional  water  to  slush  it  down.  This 
manipulation  is  modified  to  a  considerable  extent  by  different 
beatermen. 

65.  Mixed-stock  Furnish. — Some  furnishes  may  require  the 
use  of  two  or  more  kinds  of  stock  that  require  different  beating 
treatment,  such  as  rag  stock  and  bleached  sulphite  in  a  50%  rag 
bond.  It  often  happens  that  the  two  stocks  are  beaten 
separately,  and  mixed  in  proper  proportions  in  the  Jordan  chest. 
Care  has  to  be  exercised  that  there  is  proper  mixing;  and  it  is 
generally  necessar}^  to  have  a  special  mixing  chest,  similar  to  that 
shown  in  Fig.  10.  It  is  obvious  that  some  such  arrangement  will 
produce  better  paper,  for  the  severe  beating  treatment  to  which 
the  rag  half-stuff  must  be  subjected  may  be  detrimental  to  the 
sulphite.  A  similar  manipulation  is  advantageous  where  rope 
stock  and  sulphate  pulp  are  used  in  strong  bag  papers,  or  where 
rags  and  soda  pulp  are  used  in  blotting  papers.  In  some  cases, 
it  is  common  practice,  where  the  proportion  of  long  fiber  (requir- 
ing severe  beating)  is  considerably  greater  than  the  short  stock, 
to  charge  the  former  into  the  beater  by  itself,  and  it  is  partially 
beaten  before  the  addition  of  the  short  fiber.  This  method  is 
preferable  to  putting  both  stocks  in  at  once,  but  it  does  not  have 
some  of  the  advantages  of  the  separate  beating,  as  described 
above. 

66.  Book  Paper. — The  furnishes  for  book  papers  will  vary 
widely.  Relatively  cheap  raw  material  must  be  used,  and 
production  is  an  essential  factor.  A  rather  high  grade  of  book 
paper  would  consist  of  equal  amounts  of  sulphite  and  soda  pulps; 
these  would  be  furnished  to  the  beater  by  hand,  and  would  receive 
a  short  beating  of  about  2  hours.  For  a  2000-pound  beater, 
about  10  bundles  of  55%  air-dry  sulphite  pulp  or  about  1000 
pounds  of  dry  sulphite  would  first  be  added,  and  the  beater  then 
filled  up  with  soda  pulp.  Some  500  pounds  of  clay  would 
immediately  be  added,  either  dry  or  in  suspension  in  water  from 
tanks.     This  would  give  about  15%  of  loading  in  the  finished 


§3       BEATER  CONSTRUCTION  AND  OPERATION       45 

paper.  About  45  gallons  of  size  would  be  added  next  from  a  tank, 
equal  to  2  %  of  the  weight  of  the  stock.  Color  would  be  added 
shortly  afterwards,  the  roll  lowered,  and  the  alum  added  shortly 
before  dumping.  After  2  or  3  hours,  the  stuff  is  dropped  to  the 
Jordan  chest. 

Such  a  procedure  or  furnish  is  modified  to  a  great  extent  where 
pulped  magazine  stock  is  used  or  where  the  pulps  are  available 
in  the  shish  form.  In  some  cases,  the  sulphite  pulp  is  beaten 
separately,  and  the  pulped  magazine  stock  or  slush  pulps  are 
added  in  a  suitable  mixing  tank  or  chest.  Most  book  papers 
contain  clay,  or  some  similar  loading  material,  and  also  small 
amounts  of  rosin  sizing.  It  should  be  remembered  that  print- 
ing inks  are  made  with  oils,  not  water;  hence,  printing  papers 
need  not  be  water  resistant.  In  some  cases,  bleached  mechanical 
pulp  is  used  in  the  furnish,  particularly  where  the  paper  is  to 
be  used  for  current  magazines  of  little  permanent  value;  such 
pulp  is  usually  added  in  slush  form. 

67.  Newsprint. — In  general,  newsprint  is  made  of  about  70% 
to  80%  of  mechanical  pulp,  the  remainder  being  sulphite  pulp, 
both  unbleached.  Due  to  the  necessit}'-  for  low  prices,  costs  must 
be  kept  to  a  minimum,  and  production  is  of  paramount  impor- 
tance. This  tj'pe  of  paper  is  therefore  generally  made  in  a  mill 
having  a  convenient  supply  of  pulp;  and  it  is  probable  that  a 
majority  of  news  mills  use  the  pulps  in  the  slush  form,  and  have 
little,  if  any,  use  for  a  beater,  except  as  a  mixing  vat.  Very 
small  quantities  of  rosin  sizing  and  alum  are  frequently  added 
and,  in  case  of  "white"  news,  some  blue  dyes.  Any  further 
conditioning  of  the  fibers  is  done  almost  entirely  by  one  or  more 
refining  engines. 

68.  Coarse  Boards. — Probabh^  the  larger  proportion  of  the 
tonnage  of  coarse  boards  produced  have  "mixed  papers"  as  their 
chief  constituent.  In  the  production  of  such  boards  as  chip, 
binder's,  cloth,  trunk,  etc.,  the  waste  paper  is  disintegrated  in  a 
beater  or  by  special  pulping  equipment,  and  is  fed  direct  to  a 
refining  engine.  Where  combination  boards  are  being  made,  the 
stocks  for  the  different  vats  is  beaten  separately  and  dropped 
to  separate  chests. 


46  BEATING  AND  REFINING  §3 

THEORY  OF  BEATING 


ACTION,  POWER  COST,  AND  EFFICIENCY 

69.  Definitions. — Certain  terms  are  used  by  paper  makers  in 
connection  with  the  treatment  that  the  fibers  receive  in  the  beat- 
ing process.  Such  words  as  shortening,  crushing,  brooming  and 
similar  terms  are  freely  employed  in  the  language  of  the  mill  as 
though  they  were  accurately  descriptive  of  certain  phases  of 
beater  action.  Unfortunately,  however,  in  spite  of  the  fact  that 
experienced  mill  men  are  able  to  produce  at  will  close  and  dis- 
tinctive results  in  the  beater,  accurate  knowledge  regarding 
precisely  what  happens  is  limited ;  consequently,  an  exact  wording 
of  the  meaning  of  the  terms  applying  to  these  results  is  very 
difficult.  General  definitions  of  some  of  these  terms  will  now  be 
given. 

Half -stuff  is  the  fibrous  material  (pulp)  in  condition  to  go  into 
the  beater.  When  this  material  has  been  beaten,  it  is  called 
whole-stuff  or,  simply  stuff.  When  the  whole-stuff  has  been 
diluted  and  is  read}^  for  the  paper  machine,  it  is  called  stock. 
Sometimes  the  words  stock  and  stuff  are  used  interchangeably, 
but  a  distinction  should  be  made  between  them,  to  accord  with 
these  definitions.  Note  that  in  addition  to  the  fibrous  material, 
stuff  may  include  other  materials,  as  sizing,  color,  loading  (filler), 
etc. 

By  consistency  is  meant  the  per  cent  of  air-dry  paper  material 

in  the  stock  (or  stuff);  also  called  density  or  concentration.     It 

is  found  by  dividing  the  weight  of  air-dry  fiber  in  any  particular 

amount  of  stock  (stuff)  by  the  total  weight  of  the  stock  (stuff). 

Thus,  representing  the  total  weight  of  the  stock  (stuff)  by  W,  the 

weight  of  the  bone-dry  material  contained  in  it  by  w,  and  the 

,     ^  ^      iy-J-0.9  lOOOty  ,  ,         •  , 

consistency  by  C,  C  =  — ^ —  X  100  =  ^qw">  because  the  weight 

of  bone-dry  pulp  is  90%,  or  0.9,  of  the  weight  of  air-dry  pulp  or 
stock  (stuff). 

Free  stock  is  a  mixture  in  which  the  fiber  has  been  prepared  in 
such  a  way  that  when  delivered  on  a  sieve  it  forms  a  mat  through 
which  the  water  readily  drains;  this  is  an  essential  characteristic 
of  stock  for  fast-running  paper  machines,  as  for  newsprint  and  for 
papers  that  are  to  be  bulky  or  absorbent.     Slow  stock  has  been 


§3  THEORY  OF  BEATING  47 

so  prepared  that,  under  the  same  conditions,  the  water  drains 
from  it  slowly;  it  is  also  called  greasy  or  slimy,  because  of  the  feel 
of  the  stock  after  very  long  beating.  Such  stock  requires  a  slow- 
running  machine  and  increased  suction;  it  is  suitable  for  bonds, 
writings  and  parchments.  The  terms  short  stock  and  long  stock 
are  relative.  The  fibers  are  shortened  by  being  cut  in  the  process 
of  beating  or  refining,  or  both.  A  cotton  fiber,  perhaps  ^  inch 
long  originally,  may  be  shortened  considerably  and  still  be  longer 
than  a  full-length  wood  fiber  that  is,  say,  j  inch  long.  Short 
fibers  that  are  mixed  with  long  ones  tend  to  form  a  more  closely 
felted  sheet  than  long  fibers  alone.  Crushed  fibers  are  produced 
by  such  action  of  beater  or  refiner  as  may  be  thought  of  as  pounding. 
Fibers,  and  bundles  of  fibers  are  sometimes  split  lengthwise  into 
what  are  called  fibrilloe.  When  this  splitting  affects  only  the 
ends,  the  fibers  are  said  to  be  broomed.  Hydration  means  the 
taking  on  of  water  by  the  cellulose  fiber;  it  is  induced  by  the 
mechanical  action  of  the  beating  apparatus  and  the  rubbing 
together  of  the  fibers.  Hydration  results  in  a  gelatinous  film  on 
the  fiber,  which  assists  in  cementing  the  fibers  in  the  sheet. 


ACTION  OF  THE  BEATER 

70.  Mechanical  Action. — Before  discussing  the  theory  of 
beating,  it  would  be  well  to  consider  the  facts  as  to  what  results 
are  obtained  by  beating.  These  results  may  be  grouped  into  two 
classes, — mechanical  and  chemical, — which,  when  combined  to  a 
greater  or  less  extent,  produce  the  condition  of  the  stock  desired 
for  proper  felting  of  the  fibers  on  the  paper  machine.  The 
change  in  the  physical  structure  of  the  fibers  may  best  be  illus- 
trated by  photomicrographs.  It  is  to  be  noted  that  the  cotton 
fibers  in  Fig.  23,  are  quite  long  and  unbroken;  whereas,  in  Fig.  24, 
the  fibers  are  cut,  bruised,  frayed,  broomed  and  split,  and  retain 
little  of  their  former  unbroken  character.  In  this  case,  the  stock 
was  subjected  to  prolonged  beating,  to  "draw-out"  the  fibers 
with  a  minimum  of  cutting  action.  In  the  case  of  a  rag  blotting 
paper,  the  tackle  would  be  sharp,  the  consistencj-  high,  and  the 
cutting  action  greater  than  the  bruising.  In  Fig.  25  are  shown 
some  unbeaten  sulphite  fibers,^  while  Fig.  26  indicates  the  damage 
done  to  them  by  the  mechanical  action  of  the  fly  bars  and  bed 

*  Characteristic  fibers  produced  by  the  several  processes  from  wood 
are  shown  in  Section  1,  Vol.  III. 


48 


BEATING  AND  REFINING 


§3 


plate.  In  the  case  of  mechanical  pulp,  the  beating  results 
principall}^  in  a  separation  of  fiber  bundles.  Beadle '  has  shown, 
by  the  measurements  of  samples  of  stock  taken  from  the  beater 
at  frequent  intervals  during  the  beating  process,  that  the  fibers 
are  reduced  in  length,  and  that  this  reduction  takes  place  largely 


Fig.  23. 


Fig.  24. 


Fig.  25. 


Fig.  26. 


during  the  early  part  of  the  beating.     It  is,  therefore,  the  general 

rule  that,  wherever  there  is  any  considerable  beating,  the  physical 

structure  of  the  fiber  is  changed  by  mechanical  means.     The 

fibers  to  be  used  for  paper  making  are  thus  shortened,  fraj'ed, 

split,  etc.,  either  in  the  beater  or  in  the  refining  engine,  to  permit 

of  better  felting  or  interlacing  of  the  fibers  on  the  paper-machine 

'  Chapters    on   Paper  making,    Vol.    V,    by    Clayton    Beadle,    page    151, 
Fig.  29. 


§3  THEORY  OF  BEATING  49 

wire.  The  shake  of  the  wh-e  tends  to  form  a  compact  and 
uniform  fabric,  which  produces  a  better  appearance  and  a  more 
even  surface  for  printing. 

71.  Chemical  Action. — It  is  more  difficult  to  describe  or 
illustrate  the  chemical  change  produced  in  the  fibers  by  beating. 
The  simplest  statement  is  that  the  cellulose  fiber  combines  with 
water  under  certain  conditions.  This  action  is  accelerated  by 
agitation,  bj^  friction,  or  by  treatment  with  certain  chemicals. 
If  carried  to  its  extreme,  this  action  results  in  a  slimy,  gelatinous 
mass,  wherein  all  semblance  of  fiber  structure  has  been  lost; 
actual  beating  does  not  go  this  far,  but  some  of  this  slimy  sub- 
stance is  contained  in  nearly  all  high-grade  papers.  Glassine 
contains  a  high  percentage  of  such  hydrated  cellulose,  while 
blotting  paper,  in  which  it  would  detract  from  the  absorptive 
capacit}^,  has  a  verj^  small  percentage.  Stuff  that  has  been 
beaten  a  long  time  is  generally  slow  or  wet.  The  effect  of  this 
at  the  paper  machine  is  to  require  more  suction  on  the  machine 
suction  boxes,  and  to  produce  a  more  compact,  dense  sheet, 
hard  to  dry,  and  likely  to  cockle  in  drying.  The  hydrated 
cellulose  acts  somewhat  as  a  binding  material,  and  it  tends  to 
increase  the  tensile  and  bursting  strengths  of  the  paper  by  serving 
as  a  cement  or  binder;  it  produces  a  hard,  rattly,  snappy  sheet. 
When  a  soft,  limp,  absorbent  sheet  is  wanted,  the  beating  is  done 
drastically  and  quickly,  cutting  the  fibers  rapidly,  and  allowing 
as  little  time  as  possible  for  the  development  of  the  slime  or 
hydrated  cellulose. 

72.  How  the  Results  Are  Obtained. — Bearing  in  mind  the 
various  results  obtained  by  beating,  as  they  have  just  been 
described  in  general  terms,  it  is  necessary  next  to  consider  the 
ways  by  which  such  results  are  reached;  and  this  may  be  done: 
first,  with  reference  to  the  practical  operation  of  beaters  in  paper 
mills;  and,  second,  with  reference  to  the  theories  of  beating  that 
have  been  evolved  to  explain  the  facts,  as  well  as  to  assist  in 
making  improvements  on  present  designs  of  beaters. 

Take,  for  example,  the  case  where  all  of  the  pulps  that  are  to 
compose  the  final  paper  are  beaten  together  at  one  time,  for  this 
is  the  simplest  case.  After  the  beater  has  been  furnished  and  the 
roll  action  started,  there  is  nothing  added  or  taken  away;  no 
change  can  be  made  in  the  speed  of  the  roll;  no  change  can  be 
made  in  the  form,  hardness,  or  number,  of  bars  in  roll  or  bed- 
plate; the  only  manner  in  which  the  beaterman  can  influence  the 


50  BEATING  AND  REFINING  §3 

quality  of  the  final  paper  is  by  his  manipulation  of  the  roll  up  or 
down,  including  not  only  his  positioning  of  the  roll,  but  also 
the  length  of  time  of  treatment  at  any  given  roll  adjustment. 
Upon  this  one  factor,  usually  entrusted  entirely  to  the  skill  of 
the  beaterman,  rests  the  outcome;  that  is,  whether  the  final 
paper  will  or  will  not  be  of  the  required  character,  and  whether 
the  paper  machine  can  or  cannot  run  economically.  The  beater- 
man judges  the  progress  of  the  beating  by  feeling  the  stuff  with 
his  hand,  or  by  dipping  out  a  small  sample  in  a  pan  of  about  two 
quarts  capacit}^  shaking  the  stock  together  with  additional  water, 
and  observing  the  tendencies  of  the  fibers  to  clot,  or  gather. 

73.  With  the  composition  and  the  density  of  the  furnish  once 
fixed,  low  setting  of  the  roll,  giving  violent,  drastic,  punishment 
to  the  stock,  will  result  in  the  greater  physical  damage  to  the 
fibers.  If  this  be  maintained  for  a  comparatively  short  period, 
and  the  beater  then  dumped,  the  resulting  stock  will  be  free, 
comparatively  well  formed  in  the  paper,  and  the  final  paper  will 
be  soft,  inclined  to  be  fuzzy,  weak  in  tensile  and  bursting 
strength,  easj^  to  tear,  possessing  low  wearing  endurance,  and, 
unless  especially  sized,  absorbent.  Under  the  same  conditions 
in  the  beater,  if  the  roll  be  set  lightly,  and  that  setting  be  main- 
tained for  a  comparatively  long  period,  the  resulting  stuff  will 
be  slow,  and,  when  run  out  into  paper,  will  still  be  well  formed, 
but  more  cloudy,  and  the  final  paper  will  be  hard,  firm  in  surface, 
strong,  with  high  wearing  endurance,  and  in  much  less  need  of 
sizing  to  make  it  resist  water.  A  paper  produced  in  the  first 
way  will  not  take  a  high  finish  in  calendering,  whereas  a  paper 
produced  in  the  second  way  will  readily  take  high-calender 
finish.  Either  action  of  the  roll  maintained  for  a  long  enough 
period  would  result  in  slow  stuff;  but  the  two  actions  would 
not  result  in  the  same  quaHty  of  paper,  except  when  carried  out 
almost  indefinitely;  in  which  case,  the  fiber  would  entirely 
disappear  and  a  gelatinous  mass  would  remain. 

By  far  the  most  usual  procedure,  for  the  higher  grades  of 
paper,  once  the  composition  and  density  of  the  furnish  have  been 
fixed,  is  to  begin  the  beating  with  a  moderate  setting  of  the  roll 
and  then  gradually  to  lower  the  roll  at  intervals  during  the  run. 
Where  the  beating  is  done  in  this  way,  the  beaterman  must 
decide  how  hard  to  set  his  roll  at  each  change  in  setting,  when  to 
change  the  setting,  and  when  the  desired  final  result  has  been 
attained;  great  responsibility  therefore  rests  upon  the  beater- 


§8  THEORY  OF  BEATING  51 

man.  The  task  is  the  more  dehcate  because  of  the  fact,  revealed 
by  experience,  that  results  are  retarded  and  sometimes  destroyed 
by  raising  the  roll  (setting  it  less  severely)  during  the  run.  The 
roll  must  never  be  brought  upward,  but  always  progressively 
downward,  except  at  the  end  of  a  run,  especially  if  no  Jordan 
is  used,  when  the  roll  may  be  raised  a  hair's  breadth,  while  the 
fiber  is  brushed  out. 

74.  These  rules  in  beating  have  been  developed  through 
5'ears  of  operation  with  rag  stock,  and  with  other  long-fibered 
stocks,  for  the  higher  grades  of  paper.  Since  the  general  intro- 
duction of  wood  fibers  for  the  bulk  of  commercial  papers  of  all 
kinds,  refinement  of  practice  in  beating  has  tended  to  yield  to 
rapidity,  and  the  tonnage  required  of  him  leaves  the  beaterman 
little  chance  to  attend  to  progressive  roll  settings.  Most  mills 
using  wood  pulps  do  their  beating  with  a  single  setting  of  the  roll. 

The  beaterman  judges  the  setting  of  his  roll  by  two  means: 
first,  bj^  the  number  of  turns  of  the  adjusting  hand  wheel;  and, 
second,  more  finel}^  by  the  sound  that  he  gets  by  putting  one 
end  of  a  stick  on  the  bed-plate  chair  and  his  ear  to  the  other  end. 
This  same  device  tells  him  how  well  his  roll  fits  the  plate,  and 
how  accurately  round  the  roll  is  ground. 

75.  Fibrage    Theory. — Five    years'    experimenting    by    the 

Danish  engineer.  Dr.  Sigurd  Smith,  ^  have  led  him  to  w^hat  he 

terms  the  fibrage  theory  of  beating.     As  he  points  out,  if  a  steel 

rod  of  square  cross  section  is  moved  through  a  tub  of  stock,  with 

its  sharp  edge  forward,  a  certain  amount  of  fiber  will  collect 

on  that  edge ;  and  the  character  of  the  fiber  and  the  density  of  the 

mixture  in  the  tub  determine  how  much  fiber  will  thus  collect. 

Similarly,  as  the  beater  roll  turns,  the  bars  advancing  toward  the 

bed-plate  carry  with  them  a  certain  amount  of  fiber  collected 

on  the  edge.     The  roll  bars  then  advancing  across  the  bars  of  the 

bed-plate  act  on  these  fibers  in  a  manner  similar  to  the  action 

of  a  lawn-mower  on  blades  of  grass ;  that  is,  it  cuts  some  of  them 

directly,  but  damages  a  great  many  more  by  fiber  acting  upon 

fiber  within  the   mass   that  is  imprisoned  between  the   bars. 

Thus,  if  the  consistency  be  thin,  less  fibrage  will  be  collected  on 

1  The  Action  of  the  Beater  in  Paper  Making,  by  Dr.  Sigurd  Smith,  Journal 
of  the  Roval  Society  of  Arts,  Vol.  LXXI,  No.  3655,  Dec.  8,  1922.  Paper 
Trade  Journal,  \o\.  75,  No.  26:  Vol  76,  No.  1,  Dec.  28,  1922  and  Jan.  4, 
192:3.  The  Paper  Makers'  Monthly  Journal,  Vol.  60.  No.  12,  Dec.  15,  1922. 
Also  in  book  form  from  Pulp  and  Paper  Magazine  of  Canada,  or  Technical 
Association  of  the  Pulp  and  Paper  Industry. 


52  BEATING  AND  REFINING  §3 

the  edges  of  the  bars;  and  a  given  distance  between  roll  and  bed- 
plate will  result  in  less  fiber  damage  than  if  the  consistency  be 
thick  and  the  distance  between  roll  and  plate  be  the  same.  This 
conclusion  has  been  borne  out  by  actual  beating  in  the  mill. 
Acting  on  this  theory,  Dr.  Smith  has  designed  a  type  of  beating 
tackle  to  impose  on  the  stock  greater  action  without  a  proportional 
increase  in  the  power  required.  He  explains  that  to  make  the 
bed-plate  wider  would  not  increase  the  effective  beating  that 
could  be  done  under  given  conditions  in  a  given  time,  a  fact  that 
has  been  shown  in  mill  practice  many  times,  as  he  says;  and  he 
offers  as  the  reason,  that  in  going  across  a  single  plate  no  new 
fibrage  can  be  collected  on  the  edge  of  the  beater  bar,  and  a 
comparatively  narrow  plate  suffices  to  treat  as  much  fibrage  as 
is  collected  at  one  time.  By  arranging  two  plates,  however,  with 
a  properly  designed  space  between  them,  new  fibrage  can  be 
collected  on  the  beater  bars  as  they  pass  from  the  first  plate  to 
the  second;  thus  the  second  plate  can  be  made  effective  also. 

76.  The  Circulation  Theory. — Granted  that  effective  beating 
depends  mainly  on  frequent  passing  between  roll  and  bed-plate 
by  the  stock,  there  are  then  two  ways  in  which  this  may  be 
accomplished:  First,  to  increase  the  number  of  plates  under  the 
roll,  or,  what  in  principle  is  the  same,  to  increase  the  number  of 
sets  of  rolls  and  bed-plates  in  one  tub;  second,  with  one  roll  and 
bed-plate,  to  increase  the  speed  of  circulation.  By  travehng 
more  rapidly  around  the  tub,  the  stock  is  brought  more  frequently 
under  the  roll;  conversely,  a  beater  that  will  propel  a  given 
concentration  of  stock  at  a  higher  rate  of  speed  will  propel  stock 
of  a  higher  concentration  at  the  same  speed.  Stock  of  the  higher 
concentration,  as  has  been  pointed  out,  will  receive  more  damage 
to  the  fibers  in  one  passage  under  the  roll  than  stock  of  the  lower 
concentration,  the  setting  of  the  roll  being  the  same.  Thus,  there 
is  a  double  advantage  in  the  beater  that  is  so  designed  that,  with 
slight  increase  of  power,  it  can  propel  the  stock  at  a  higher  speed ; 
the  effective  beating  may  be  increased  either  by  reason  of  higher 
speed  of  circulation,  or  by  reason  of  higher  concentration.  In 
practice,  the  newer  designs  that  have  been  offered  accomplish 
much  in  both  directions. 

77.  Most  Efficient  Degree  of  Concentration. — An  ingenious 
method  has  been  evolved  for  finding  the  consistency  of  stock  that 
will  enable  a  given  beater  to  perform  most  efficiently;  that  is,  do 


§3 


THEORY  OF  BEATING 


58 


a  given  amount  of  work  on  the  stock  with  the  least  expenditure 
of  power  per  ton  of  paper  produced.  Based  on  the  assumption 
that  50  times  under  the  roll  completes  the  beating,  a  series  of 
tests  were  made  on  a  given  furnish  at  different  consistencies, 
wherein  the  consistency,  the  speed  of  travel  (circulation),  and 
the  power  input  to  the  motor,  were  measured;  and  these  tests 
led  to  the  following  table: 


Per 

Speed 
of 

Minutes 

No.  of 

No.  of 

No.  of 

No.  of 

cent 

Pounds 

travel 

required 

dumps 

pounds 

tons 

horse- 

con- 
sist- 

air-dry 
stock 

in  feet 
per 

to  turn 
50  times 

per  24 
hours 

air-dry 
stock  per 

per 

dav 

power- 
hours 

ency 

minute 

24  hours 

per  ton 

0 

0 

141 

15.4 

0.0 

0 

0.0 

0.0 

1 

300 

111 

19.4 

74.0 

22,200 

11.10 

6.75 

2 

600 

80 

26.9 

53.5 

32,100 

16.05 

4.68 

3 

900 

55 

39.0 

37.0 

33,300 

16.65 

4.51 

4 

1200 

33 

65.0 

22.2 

26,600 

13.30 

5.64 

5 

1500 

20 

107.5 

13.4 

20,100 

10.05 

7.47 

6 

1800 

10 

210.0 

6.85 

12,330 

6.16 

12.18 

7 

2100 

4 

537.5 

2.68 

5,630 

2.80 

26.80 

8 

2400 

1 

2150.0 

0.68 

1,610 

0.80 

93.70 

These  figures  plotted  in 
the  form  of  a  chart  are 
shown  in  Fig.  27.  The  chart 
brings  to  view  more  forci- 
bly the  fact  that  with  this 
beater,  and  the  particular 
stock  with  which  it  was  fur- 
nished, the  greatest  produc- 
tion per  day  occurred  when 
the  consistency  was  3%,  and 
at  that  same  consistency,  the 
power  consumed  per  ton  of 
stock  was  least.  If  the  con- 
sistency could  be  increased 
without  reducing  the  speed 
of  travel,  and  without  in- 
creasing the  power  con- 
sumed proportionately,  then 


Pounds  per  Charge 

,.„0     JOO     600    900    IMO     1500    1800  2100   2400 
140 

ijo  V 

4        ^ 

120  ^_ 

^ 

"°    At-      4^ 

i_^ 1 

100            100     100         \_     1        1                        ~t^     " 

A                 "^ 

90            90      90 

o       -        ^V 

80     20     80     80          S)  \ 

"        V  v-ii 

TO       cio|  70        T    V                               j;: 

i  >        ^  ^z^^          ^" 

^-gjs^^fe^m       vA     \          _i_i 

^  %  ^              4li        >            XI 

sat  ^^  50         .^    ^      r         +t^ 

1 1-         t  ^  A     \     xr~ 

wJlOlAO      40          S         V       .         \                     r 

^vlS      V         7  ^ 

30            30      30                          ^tV       \             I 

^^^     ^     -J 

20     S      20      20                                 S^     ^     T"         j 

'^5:Jx     d 

10            10      10                                       \^^            -t 

®    ®   ®    (L    %^_~          ^--^^^^    ^ 

0    0     P...  0     ..,.  ,^       '^ZL    ^^i.J 

U               2^45679 

Per  Ceirl'  Consisl-ency 

Fio.  27. 


54  BEATING  AND  REFINING  §3 

the  efficiency  of  this  beater  would  be  increased;  or  if  the  speed 
of  travel  could  be  increased  without  reducing  the  consistency, 
and  without  increasing  the  power  consumed  proportionately,  then 
the  efficiency  of  this  beater  would  be  increased.  To  do  either 
would  require  changes  in  the  design  of  the  beater. 

78.  The  Viscosity  Theory. — Experiments  leading  to  the  two 
foregoing  theories  have  rested  on  the  observed  behavior  of  the 
stock  in  going  over  the  paper  machine,  and  on  the  quality  of  the 
final  paper.  The  subject  has  been  treated  in  this  country  from 
a  radically  different  angle.  Thus,  the  first  step  of  the  series  of 
tests  was  to  develop  means  by  which  small  pulp  sheets  could  be 
formed  under  exactly  standard  conditions;  so  that  they  could  be 
tested  in  all  of  the  known  ways  separately,  and  conclusions  could 
be  drawn,  independently  of  the  manner  in  which  the  beaten  stock 
might  be  treated  in  the  refiner  or  on  the  paper  machine.  More- 
over, such  sheets  were  made  from  samples  of  the  stock  taken 
from  the  beater  at  regular  intervals  during  the  beating;  and,  in 
this  way,  charts  were  constructed  showing  the  changes  made  in 
bursting  strength,  folding  strength,  sizing,  shrinkage,  and  bulk, 
separately,  as  related  to  the  setting  of  the  roll,  the  pressure  exerted 
by  the  roll  on  the  bed-plate,  the  speed  of  circulation,  consistency, 
and  power  consumed.  It  was  found,  for  example,  that  a  given 
amount  of  beating,  applied  to  a  given  stock  at  a  given  consistency, 
often  increases  bursting  strength,  but  decreases  folding  strength, 
as  compared  with  a  less  amount  of  beating;  and  the  question 
arises,  which  manner  of  beating  should  be  considered  more  effec- 
tive. In  other  words,  it  is  in  many  cases  misleading  to  assert 
that  a  certain  roll  action,  or  a  certain  number  of  passages  under 
the  roll,  constitute  a  given  amount  of  beating;  for  such  an  assump- 
tion does  not  take  into  consideration  all  the  facts.  The  amount 
of  beating  must  be  judged  primarily  by  the  particular  qualities 
in  the  final  paper  that  it  is  desired  to  have;  then  that  manner  of 
beating  best  adapted  to  enhance  those  qualities  is  the  one  to  be 
selected. 

The  tests  were  carried  out  in  the  way  described  for  seven  years 
under  a  great  variety  of  conditions,  for  the  purpose  of  finding 
some  method  of  so  directing  the  beating  of  stock  as  to  be  able  to 
repeat  in  a  succeeding  furnish  of  stock  the  same  qualities,  at  the 
end  of  the  beating,  that  had  been  produced  in  a  previous  furnish 
of  stock.  The  key  to  the  problem  was  finally  found  when  it  was 
discovered  that  changes  in  frictional  resistance  in  the  stock 


§3  THEORY  OF  BEATING  55 

have  a  direct  bearing  on  the  quaHties  of  the  final  paper.  With  a 
given  furnish  and  a  given  consistency,  the  action  of  the  beater 
results  in  changes  in  the  surface  friction,  and  internal  friction,  of 
the  stock.  If  these  changes  are  made  in  the  same  way  and  to  the 
same  degree  in  one  furnish  after  another,  the  final  paper  will 
possess  the  same  qualities. 

CONTROL  OF  BEATING 

79.  Two  Ways  of  Controlling. — There  are  two  ways  of  attack- 
ing the  problem  of  control  of  beating:  one  way  is  to  control  the 
setting  of  the  roll  directly;  the  other  way  is  to  control  the  setting 
of  the  roll  through  measurement  of  the  results  of  roll  action  on  the 
stock.  Bj'-  the  first  method,  the  control  of  the  roll  directly, 
either  the  distance  between  the  roll  and  the  bed-plate,  or  else  the 
weight  exerted  by  the  roll  on  the  bed-plate,  can  be  the  factor 
chosen  for  control.  But  it  must  be  clear  at  the  outset,  and 
always  kept  in  mind,  that  if  a  beaterman  is  to  be  required  to  set 
the  roll  at  the  same  distance  above  the  bed-plate  every  time,  or 
if  he  is  to  be  required  to  set  it  upon  the  bed-plate  with  a  given 
pressure  each  time,  he  must  have  some  method  of  getting  the 
beater  furnished  to  the  same  depth  and  with  stock  of  the  same 
densitj'';  otherwise,  these  mechanical  elements  of  control  cannot 
be  expected  to  give  uniform  results. 

When  no  special  instructions  or  apparatus  are  given  to  the 
beaterman,  the  condition  of  the  stock  and  the  manipulation  of 
the  roll  are  determined  by  him  by  the  feel  of  the  stock,  or  by  the 
use  of  a  small  bowl  or  copper  dipper,  of  about  2-quart  capacity. 
Into  this  bowl,  a  small  portion  of  stock  is  mixed  with  a  relatively 
large  quantity  of  water,  and  the  appearance  of  the  fibers  and  the 
absence  of  small  clots  or  bunches  of  fibers  are  an  assistance  in 
judging  the  condition  of  the  stock  in  the  beater.  Often  two 
vessels  are  used,  and  the  stock  is  observed  as  it  passes  over 
the  edge  of  one  to  the  other.  Also  refer  to  description  of  blue 
glass  test  in  Section  3,  Vol.  III. 

80.  Control  of  Density. — A  prime  requirement  of  control  of 
beating,  then,  is  control  of  density  (consistency)  of  the  furnish, 
that  is,  of  the  percentage  of  paper-making  material  in  the  stock 
In  one  or  two  mills  where  this  problem  has  received  careful 
attention,  methods  have  been  worked  out  for  weighing  the  pulp 
into  the  beater  and  measuring  in  the  water.     But  pulp  comes  to 


56 


BEATING  AND  REFINING 


§3 


the  mill  in  many  forms  and  at  different  moisture  contents;  and  to 
be  weighed  correctly,  it  must  be  reduced  to  the  same  moisture 
basis.  A  very  effective  device  for  doing  this  is  a  small  centri- 
fuge, such  as  is  used  by  laundries  for  a  preliminarj'-  drying  of 
clothing.  It  has  been  found  by  experiment  that  a  sample  of  wet 
stock,  properly  treated  in  a  centrifuge,  will  always  come  out  at  a 
uniform  moisture  content.  In  order  to  compute  the  weight  at  any 
moisture  content,  it  is  only  necessary  to  know  what  per  cent  of 
moisture  exists;  therefore,  the  sample  that  is  treated  in  the  centri- 
fuge gives  the  basis  for  all  calculations  regarding  moisture;  it 
gives  the  beater-room  management  data  for  computing  exactl}'^ 
what  quantities  of  the  various  stocks  are  to  be  weighed  in,  to 
fill  a  given  furnish,  and  what  quantities  of  water  to  add.  Until 
this  method  was  devised,  the  problem  of  furnishing  definite 
amounts  of  stock  from  the  drainer,  for  example,  has  been  almost 
beyond  precise  control. 

81.  A  Consistency  Regulator. — A  successful  type  of  consistency 
regulator  widely  used  on  wood  pulps  is  shown  in  Fig.  28.     Stuff 


Fig.  28. 

enters  the  constant-head  box  N,  in  the  bottom  of  which  is  a  round 
orifice  M  in  a  brass  plate.  A  constant  head  is  maintained  by 
admitting  m.ore  stuff  through  pipe  L  (pumped  at  a  constant  rate 
from  the  pulp  tank  or  Jordan  chest)  than  can  pass  through  the 
orifice  M,  the  excess  overflowing  the  baffle  into  pipe  /,  which 
conducts  it  back  to  the  chest.  That  part  of  the  stuff  that  flows 
through  orifice  M  passes  through  pipe  0  into  the  variable  level  or 
weighing  chamber  H,  which  is  mounted  on  a  scale  beam  J  that 
balances  on  knife-edge  bearings  at  P.     The  counterweight  K 


§3  THEORY  OF  BEATING  57 

may  be  moved  along  the  other  arm  of  the  beam  as  in  any  weigh- 
ing machine,  and  is  used  to  balance  H  and  its  contents. 

82.  Now  it  is  well-known  that  the  friction  of  stuff  flowing  in 
pipes  varies  with  changes  in  consistency;  also,  if  a  relatively 
constant  volume  of  stuff  is  to  pass  through  a  pipe  of  given  size, 
it  will  require  a  greater  head  (or  pressure)  to  maintain  the  same 
flow  when  the  consistency  of  the  stuff  is  increased.  This  fact  is 
made  use  of  in  the  following  manner: 

Through  a  small  bj'pass,  taken  off  from  the  main  stuff  pipe, 
as  close  as  convenient  to  the  stuff  pump,  sufficient  stuff  is  con- 
tinuously drawn  to  maintain  an  overflow  in  the  head  box  A^  of  the 
regulator,  thus  maintaining  a  constant  head  on  the  orifice  M,  and 
producing  a  constant  flow  in  the  pipe  0.  Since  this  orifice  offers 
a  minimum  of  frictional  resistance  to  the  passage  of  the  stuff,  the 
amount  discharged  through  it  to  the  variable-level  chamber  H 
beneath  it,  will  vary  but  little  with  changes  in  consistency.  In 
passing  from  the  variable-level  chamber  H,  however,  the  stuff 
meets  with  considerable  frictional  resistance,  which  is  gov- 
erned by  the  reducing  elbow  R  and  by  the  size  and  length  of  the 
goose-neck  outlet  pipe  S,  w'ith  the  result  that  the  level  in  H  rises 
a  sufficient  amount  to  overcome  the  resistance  of  the  reducing 
elbow  R  and  pipe  S,  and  maintains  the  flow.  Thus,  when  the 
consistency  of  the  stuff  increases,  the  level  in  chamber  H  rises; 
and  when  the  consistency  decreases,  the  level  in  chamber  H  falls. 

A  water-supply  pipe  A  is  connected  to  the  inlet  of  the  stuff 
pump  (which  supplies  stuff  to  be  regulated)  by  means  of  a  gate 
valve,  the  stem  of  which  is  connected  to  a  screw  B  passing 
through  a  double-faced  ratchet  wheel  C.  A  pawl  D  is  provided 
for  rotating  the  ratchet  wheel  in  either  direction;  a  set  of  links  E 
connects  the  scale  beam  /  of  the  regulator  and  the  pawl;  a  shaft 
F  connects  with  an  eccentric  for  operating  the  pawl ;  and  a  safety 
stop  disengages  the  pawl  when  the  valve  is  wide  open  or  shut. 

83.  Stock  of  a  given  kind  at  a  given  consistency  will  fill  weighing 
chamber  77  to  a  definite  height;  that  is,  where  enough  head  is 
created  above  goose-neck  pipe  S  to  cause  a  rate  of  flow  equal  to 
the  flow  through  orifice  M.  Thus,  a  definite  weight  of  stock 
plus  metal  is  estabhshed  for  any  desired  consistency  of  stock; 
and  this  weight  corresponds  to  such  setting  of  counterweight  K 
as  will  balance  it.  The  counterweight  K  is  set  to  balance  the 
weight  of  the  chamber  //  and  its  contents  at  the  desired  consis- 


58  BEATING  AND  REFINING  §3 

tency,  and  when  K  and  H  are  iu  balance,  pawl  D  will  not  engage 
with  either  side  of  the  ratchet.  If  the  consistency  of  the  stuff 
increases,  the  additional  frictional  resistance  will  cause  the  stuff 
to  back  up  in  chamber  H,  increasing  the  weight  of  the  stuff  in 
the  chamber  (since  the  level  of  the  stuff  in  the  chamber  rises); 
this  brings  down  that  end  of  the  scale  beam  to  which  chamber  H 
is  attached,  and  causes  the  other  end,  with  the  counterweight,  to 
rise;  this  movement  is  transmitted  by  the  links  E,  which  cause 
the  pawl  D  to  engage  with  the  ratchet  wheel  C,  and  rotates  the 
ratchet  wheel.  Since  the  ratchet  wheel  cannot  move  sideways, 
it  Avill  cause  the  screw  B  (to  which  it  is  threaded)  to  back  out  and 
open  the  water-inlet  valve  until  sufficient  water  is  added  at  the 
pump  to  reduce  the  total  volume  of  stuff  passing  through  the 
pump  to  the  proper  consistency.  When  this  occurs,  the  scale 
beam  again  becomes  horizontal,  the  pawl  comes  to  neutral  posi- 
tion, engaging  neither  side  of  the  ratchet,  and  the  water  valve 
remains  open  the  necessary  amount.  If,  now,  the  stuff  becomes 
too  thin  and  less  water  is  required,  an  opposite  movement  (due 
to  the  same  causes  as  just  described)  will  close  the  valve  the 
necessary  amount.  A  safety  stop  disengages  the  pawl  when  the 
limits  of  the  valve  travel  are  reached. 

If  sufficient  care  be  taken  to  insure  proper  operating  conditions, 
stuff  can  be  controlled  with  this  apparatus  with  a  maximum 
relative  variation  of  5%  over  or  under  the  desired  consistency. 
The  same  apparatus  may  be  attached  to  the  pump  and  pipe 
system  delivering  any  kind  of  stuff  fj'om  the  Jordan  chest, 
through  the  constant-head  regulating  box  to  the  Jordan,  or  from 
the  machine  chest  to  the  paper  machine. 

84.  Instead  of  separate  constant-flow  regulating  boxes  deliver- 
ing stuff  of  uniform  density  to  the  mixing  tank,  there  may  be  used 
an  automatic  proportioning  device  recently  developed.  This 
consists  essentially  of  the  required  number  of  constant-level  stuff 
chambers,  from  which  stuff  is  delivered  through  flat  openings, 
which  are  provided  with  a  slide  valve  that  opens  one  part  as  it 
closes  the  other.  With  the  proper  proportions  of  pulp  in  constant 
quantity  at  uniform  consistency  thus  insured,  it  is  possible  to  add 
color,  size,  clay,  etc.,  in  solution  or  suspension  in  just  the  right 
amount. 

85.  Consistency  Indicator. — The  beater  drag,  Fig.  29,  gives 
control  of  the  consistency  of  the  furnish;  accomphshed  by  bring- 


§3 


THEORY  OF  BEATING 


59 


ing  the  arrow  L  to  a  prescribed  point  and,  at  the  same  time,  hav- 
ing the  beater  filled  to  exactly  the  same  depth.  This  result  is 
effected  most  readily  if  one  kind  of  stock  is  coming  to  the  beaters 
in  slush  form;  for,  in  that  case,  a  steady  stream  of  slush  stock  may 
be  run  in  while  water  is  taken  out  b}''  means  of  a  cylinder  washer, 
thus  maintaining  the  proper  depth  in  the  tub,  until  the  arrow 


Fig.  29. 


stands  at  the  right  point  on  the  scale.  This  method  is  suffi- 
ciently accurate  in  careful  hands  to  control  the  consistency  of  the 
furnish  within  a  relative  variation  of  2%. 

86.  Controlling  Consistency  at  the  Jordan. — In  mills  wheie  no 
method  has  been  adopted  for  the  control  of  the  densitj''  factor,  it 
is  customary  to  compensate  for  the  fluctuation  by  adding  water 
at  the  Jordan,  adding  more  when  the  stock  seems  thick  and  less 
when  it  seems  thin.  However,  since  density  is  the  starting  point 
in  the  control  of  beating,  the  better  plan  is  to  maintain  uniform 


60  BEATING  AND  REFINING  §3 

consistenc}',  when  once  obtained,  from  the  beaters  to  the  paper 
machine;  this  may  be  done  by  adding  the  proper  amount  of  water 
in  dumping,  so  that  the  consistency  of  the  stock  in  the  chest  is 
kept  uniform.  A  very  satisfactory  device  for  this  purpose  is  the 
recording  liquid-level  gauge,  since  paper  pulps  are  of  prac- 
tically the  same  weight  as  water.  The  diaphragm  of  the  record- 
ing liquid-level  gauge  is  placed  well  down  in  the  chest;  when  it 
shows  that  the  surface  of  the  stuff  in  the  chest  has  fallen  to  a 
certain  level,  the  next  beater  is  dumped,  and  the  proper  amount  of 
water  is  used  in  dumping  to  bring  the  surface  of  the  stuff  up  to 
a  higher  prescribed  level.  If,  then,  this  predetermined  amount  of 
dumping  water  is  made  such  that  the  resulting  consistency  in  the 
Jordan  chest  is  right  for  passing  through  the  Jordan,  no  water  has 
to  be  added  at  the  Jordan,  and  the  uniformitj^  of  consistency  once 
established  in  the  beater  is  maintained  up  to  the  paper  machine. 
It  has  been  found  that  this  factor  can  be  so  well  controlled  that 
ream  weights  on  the  machine  almost  maintain  themselves. 

87.  Control  by  Setting  of  Roll. — Returning  now  to  the  plan  of 
controlling  by  changing  the  setting  of  the  beater  roll,  the  same 
results  in  the  stock  will  not  be  produced  by  the  same  position  of 
the  roll  or  the  same  roll  pressure,  as  has  already  been  shown, 
unless  the  consistency  is  the  same.  But  even  with  the  consis- 
tency uniform,  the  quahty  of  the  stock  coming  to  the  beater  varies. 
Some  stocks  require  drastic  roll  action  and  some  less  drastic 
action,  for  uniform  results  in  the  paper.  That  which  requires 
less  treatment  will  get  over-treated,  by  being  subjected  to  the 
same  roll  setting,  as  compared  with  that  which  requires  more 
treatment,  and  the  independent  means  of  governing  the  roll 
setting  would  thus  fail  to  compensate.  This  method  has  been 
the  subject  of  many  careful  experiments,  in  which  both  of  the 
mechanical  methods  of  governing  the  roll  setting  were  employed. 
To  obtain  control  of  beating,  therefore,  it  is  necessary  to  develop 
some  measuring  unit  to  express  the  result  of  beater  treatment  on 
the  stock. 

88.  Watt  Meter  Control. — It  has  been  stated  that  a  large 
pa,rt  of  the  power  used  in  beating  is  consumed  in  circulating  the 
stock;  with  any  one  beater,  this  power  consumption  will  be 
constant  for  the  same  furnish  and  consistency.  Any  variation 
in  the  power  consumed  will  then  be  caused  by  a  change  in  the 
adjustment  of  the  roll  and  its  consequent  pressure  on  the  bed- 


§3  THEORY  OF  BEATING  61 

plate  and  effect  on  the  stuff.  Any  changes  in  power  consumption 
are  immediately  reflected  in  the  reading  of  a  watt  meter  in 
circuit  when  only  one  beater  is  driven  from  a  single  electric 
motor.  By  using  a  reliable  recording  watt  meter,  a  curve  is 
drawn  that  serves  as  a  control  and  guide;  and  by  dupHcating 
the  curve,  it  is  possible  to  duplicate  beating  conditions  very 
closely,  although  for  really  accurate  work,  this  method  is  probably 
not  so  dependable  as  some  others,  because  of  the  elements  of 
beating  action  which  it  leaves  out  of  account, 

89.  The  Beater  Drag. — The  theory  of  beating  control  will  be 
discussed  later;  but  it  may  here  be  stated  that  the  roll  counter- 
poise and  the  Wallace-Masson  beater-roll  regulator  both  operate 
to  govern  mechanically  the  setting  of  the  roll,  whereas  the 
beater  drag,  shown  in  Fig.  29,  measures  the  changes  produced 
in  the  stock  by  beating. 

Referring  to  Fig.  29,  a  square  shaft  S  spans  the  channel  of 
the  beater  opposite  that  in  which  the  roll  runs;  it  is  supported 
on  guides  at  its  ends,  which  are  arranged  to  lift  and  fall  on  stan- 
chions, through  a  distance  sufficient  to  permit  the  drag  to  be 
lifted  up  out  of  the  tub  during  the  dumping  and  furnishing 
operations.  Fastened  to  the  shaft  S  and  held  rigid  by  it  is  a 
frame  W,  which,  in  turn,  carries  a  bearing  B,  by  means  of  which 
an  oval  rod  R,  free  to  swing  slightly,  is  hung  vertically.  In 
Fig.  29,  the  stock  is  supposed  to  be  traveling  from  left  to  right. 
Rod  R  is  anchored  back  to  frame  W  through  a  coiled  spring, 
enclosed  in  spring  case  C  There  is  a  pivot  bearing  at  P,  which 
carries  a  light-weight  bell-crank  lever  L,  on  the  outer  end  of 
which  is  an  arrowhead,  which  runs  up  and  down  across  scale  U. 
The  inner  end  is  connected  by  link  V  to  the  oval-rod  bearing 
bracket  Y.  At  the  lower  end  of  rod  R,  is  a  smooth  body  or  bulb 
H  of  proper  shape,  perhaps  lemon-shaped.  As  the  stock  thick- 
ens and  creates  a  greater  pull  against  this  bulb,  the  rod  R  swings, 
which  motion  is  conveyed  through  F  to  L;  this  causes  L  to 
rotate  about  P,  and  thus  deflects  the  arrowhead  upward;  but 
when  the  stock  is  made  thinner,  the  pull  diminishes,  and  the 
arrowhead  falls.  Each  position  of  the  arrowhead  is  recorded 
automatically  by  suitable  clock-work  mechanism. 

As  the  beating  progresses,  a  curve  is  automatically  drawn 
on  a  chart,  which  represents  the  varying  degree  of  pull  exerted 
by  the  stock  against  the  bulb  H.  If  the  stock  is  furnished  to 
a  fixed  depth  in  the  tub  at  the  beginning  of  the  run,  and  the 


62 


BEATING  AND  REFINING 


§3 


arrowhead  is  brought  to  a  predetermined  point  on  the  scale,  the 
density  of  the  furnish  is  thereby  made  uniform.  The  combi- 
nation of  a  fixed  furnishing  point  and  a  given  curve  on  the 
record,  composes  the  basis  for  instructions  as  to  the  beating; 
and  the  record  of  the  recorder  provides  the  history  of  every 
run,  which  may  be  compared  with  the  instructions  issued. 

90.  Experiments  extending  over  five  years,  made  both  in  the 
laboratory  and  under  actual  mill  conditions,  resulted  in  establish- 


FiG.  30. 


ing  the  following  principle:  The  mass  of  stock  in  the  beater  is 
treated  as  a  fluid  mass,  such  as  molasses;  and  the  friction  of 
this  fluid  mass  on  bodies  that  are  made  to  move  through  it  is 
measured,  coupled  with  the  friction  of  this  mass  when  rubbing 
on  itself.  In  other  words,  both  the  internal  and  surface  frictions 
of  the  mass  are  measured.  As  the  beating  progresses,  these 
frictional  factors  change.  A  typical  curve,  as  drawn  by  the 
automatic  recording  attachment,  is  shown  in  Fig.  30.  The 
principle  is,  then,  that  if  this  curve  is  reproduced  each  time  that 
the  same  furnish  is  made  in  the  same  beater,  the  quality  of  the 
resulting  paper  will  be  uniform. 

91.  In  Fig.  30,  each  horizontal  line  represents  10  points  on 
the  scale  of  the  beater  drag.  The  consistency  of  the  furnish  was 
determined  by  thickening  with  cylinder  washer  (Art.  42)  to  point 
A.  Thickening  was  continued  until  room  was  made  in  the  tub  for 
the  size  and  clay,  both  in  milk  form,  and  they  were  added  at 
point  B,  bringing  the  pointer  down  to  C,  where  the  first  reading 


§3  THEORY  OF  BEATING  63 

was  taken.  It  is  interesting  to  note  at  point  E,  where  the  alum 
was  added,  that  this  had  a  marked  effect  on  the  reading,  raising 
it  about  30  points.  To  repeat  this  curve  with  the  same  furnish, 
instructions  are  given  in  the  form  of  a  table  of  readings,  one 
reading  for  each  period  of  time,  say  15  or  20  minutes,  throughout 
the  run;  the  beaterman  adjusts  his  roll  as  the  riin  proceeds,  in 
such  a  way  as  to  follow  out  the  readings  as  set,  and  thus  duplicate 
the  curve.  Each  different  beater  of  the  set  on  the  same  furnish 
requires  a  different  curve,  because  beaters  do  not  have  the  same 
action  on  the  stock,  even  when  in  the  same  condition  of  repair  or 
wear. 

Although  this  principle  has  not  been  applied  in  daily  practice 
to  other  than  short-fibered  stocks,  a  sufficient  number  of  experi- 
ments have  been  made  to  indicate  that  it  has  universal  applica- 
tion. Long-fibered  stocks  require,  however,  a  different  form  of 
measuring  device — one  that  will  avoid  snagging.  But  the  rela- 
tionship between  the  frictional  resistances  and  the  quality  of  the 
stock  is  apparently  a  universal  principle,  in  connection  with  the 
beating  of  stock  for  paper. 

92.  Control  by  Measurement  of  Freeness. — The  freeness  of 
stock  prepared  for  making  paper  decreases  with  the  increased 
degree  of  hydration  of  the  fiber.  The  progress  of  this  action  may 
be  followed  and  measured  relatively  by  determining  the  rate  at 
which  water  will  drain  from  the  stock  at  standard  temperature 
and  consistenc3^  The  effect  of  temperature  is  not  always  fully 
appreciated;  it  is,  however,  very  important,  since  water  at  its 
boiling  point  drains  about  five  times  as  fast  as  water  at  the 
freezing  point.  It  is  also  obvious  that  results  can  be  compared 
only  when  referred  to  stock  of  the  same  consistency.  Fig.  31 
shows  an  apparatus  used  in  a  number  of  mills  for  measuring 
the  freeness  of  the  stock;  it  is  operated  as  follows:  A  cer- 
tain quantity,  say  a  quart,  of  stock  from  the  beater  is  poured 
into  a  sieve  having  a  fine-wire  screen  bottom.  This  is  placed  over  a 
coarsely  perforated  or  grooved  plate,  a  piece  of  felt  is  laid  over 
the  stock,  and  is  pressed  down  with  a  weight  for  a  definite  time. 
A  prehminary  test  will  show  about  how  much  bone-dry  fiber 
is  in  the  pressed  cake.  On  the  assumption  that  this  is  nearly 
constant  for  the  class  of  fiber  used,  enough  pressed  fiber  is  taken 
to  make  about  1000  c.c.  of  a  suspension  containing  1  per  cent  of 
fiber.  Another  portion  of  the  cake  is  weighed  and  tested  for 
moisture  content.     (A  correction  factor  can  be  applied  to  the 


64 


BEATING  AND  REFINING 


§3 


test  result,  if  necessary.)  Thus,  if  the  cake  contained  50% 
moisture,  20  grams  would  be  required  to  furnish  the  10  grams  to 
be  mixed  with  990  grams  (approximately  990  c.c.)  of  water. 

93.  When  thoroughly  mixed,  cool  or  warm  to  the  temperature 
selected  as  the  standard,  and  fill  the  container  A,  Fig.  31,  to  the 
mark,  having  first  clamped  the  bottom  and  poured  in  water  to 
the  level  of  the  wire  screen  B.     The  cover  is  then  screwed  on, 

with  the  cock  open ;  with  cover  closed, 
the  cock  is  closed,  and  there  is  no  air 
pressure  in  A.  The  container  is 
placed  over  the  funnel  C,  a  vessel  is 
placed  under  the  bottom  outlet  D, 
and  the  side  outlet  E  is  supplied  with 
a  graduated  cylinder  F.  The  bottom 
of  the  container  is  opened  quickly  and 
kept  from  swaying  back,  and  the  cock 
in  the  cover  is  immediately  opened. 
Water  at  once  flows  into  the  funnel, 
rapidly  at  first,  then  at  a  diminishing 
rate.  While  the  rate  of  flow  to  C  ex- 
ceeds the  capacity  of  outlet  D  the 
excess  overflows  through  E  to  the 
graduated  cylinder  F.  When  the 
rate  of  flow  to  C  falls  below  the  capa- 
city of  outlet  D,  the  overflow  through 
E  is  automatically  cut  off.  In  the 
case  of  free  stock,  this  cut-off  from  E 
is  relatively  late;  in  case  of  slow 
stock  it  is  relatively  early.  Free  stock 
will  dehver  more  water  to  graduated 

cylinder  F  than  will  slow  stock.     The  amount  of  water  in  /^  is  a 

measure  of  the  freeness  of  the  stock. 

Curves  showing  the  variation  in  freeness  can  be  drawn,  and 

results  can  be  fairly  well  duplicated  with  respect  to  those  qualities 

controlled  or  indicated  by  this  measurement. 

94.  A  small  v^entrifuge  may  be  used  for  de-watering  the  sample, 
giving  a  uniform  fiber  content.  Charts  and  curves  may  be 
prepared  for  correcting  results  of  tests,  both  for  temperature 
and  for  consistency.  By  using  such  correction  factors  instead 
of  waiting  to  bring  conditions  of  test  to  standard,  fairly  accurate 
indications  tnay  be  obtained  much  more  quickly. 


Fig.  31. 


§3  REFINING  65 

QUESTIONS 

(1)  Explain  the  operation  of  the  roll  counterpoise.     What  advantage  is 
taken  of  this  principle  in  the  Wallace-IMasson  attachment? 

(2)  Describe  one  type  of  continuous  beater  attachment. 

(3)  How  does  the  beaterman  know  how  close  the  roll  is  to  the  bed-plate? 

(4)  What  differences  in  beating  would  produce  a  soft  paper  or  a  hard,  rattly 
paper  from  the  same  furnish  of  stock? 

(5)  (a)  Why  is  loading  used  in  some  papers?     (b)  Should  loading  be 
considered  adulteration? 

(6)  What  parts  of  the  beaterman's  duties  could  be  served  better  if  he  had 
some  knowledge  of  chemistry? 

(7)  In  what  way  would  you  consider  the  microscope  helpful  in  controlling 
the  beating  operation? 

(8)  How  is  freeness  (or  slowness)  measured,  and  what  does  the   result 
obtained  indicate? 


REFINING 


REFINING  ENGINES 


THE  JORDAN 

95.  Importance. — The  refining  engine,  as  shown  at  H  in  Fig.  20, 
is  not  a  necessary  part  of  the  beating  equipment;  but,  because 
of  its  usefulness  as  a  means  of  preparing  a  stock  that  will  form  well 
on  the  paper  machine,  it  is  found  in  all  mills  of  large  production, 
and  in  most  fine  mills;  while  in  mills  maldng  a  low  grade  of  paper, 
it  has  surpassed  in  importance  the  beater  itself.  The  most 
common  type  of  refining  engine  is  the  Jordan,  named  after  its 
inventor. 

96.  Description. — A  typical  design  of  a  Jordan  engine  is  shown 
in  Fig.  32.  The  working  parts  are  conical  in  shape;  they  consist 
of  a  shell  S,  within  which  a  plug  R  revolves,  and  to  which  it  fits. 
Plug  R  is  rigidly  attached  to  a  shaft,  which  turns  in  three  bearings 
B,  and  is  driven  (in  the  case  of  a  belt  drive)  by  pulley  P.  Many 
Jordan  engines  are  now  installed  to  be  direct-driven  by  electric 
motor,  in  which  case,  the  motor  is  placed  in  line  with  the  shaft 
of  the  Jordan,  and  is  direct-connected  to  it  bj'  means  of  a  special 
coupling,  which  permits  horizontal  movement  of  the  plug,  toward 
or  from  the  motor.  In  some  designs  of  direct  drive,  motor, 
plug  shaft  and  plug,  move  together. 


66 


BEATING  AND  REFINING 


13 


The  Jordan  is  adjusted  to  govern  its  action  on  the  stock  by 
moving  the  plug  horizontally,  thus  bringing  its  surface  nearer  to 
or  farther  from  the  inside  surface  of  the  shell.  This  action  is 
similar  in  effect  to  the  adjustment  of  the  beater,  when  the  roll  is 
moved  toward,  or  from  the  bed-plate.  In  the  case  of  the  beater, 
the  surface  of  contact  between  the  roll  and  bed-plate  is  very 
narrow — almost  a  line — while  in  the  Jordan,  the  surface  of 
contact  is  the  entire  inside  surface  of  the  shell.  In  the  beater, 
the  direction  of  movement  of  the  roll  during  adjustment  is  at 
right  angles  to  the  axis  of  the  roll;  but  in  the  Jordan,  it  is  parallel 
to  the  axis  of  the  plug.     To  effect  this  latter  movement,  the 


Secfion  A-A 


Fig.  32. 


bearing  shown  at  the  large  end  of  the  cone  is  a  thrust  bearing,  to 
enable  it  to  withstand  pressure  action  lengthwise  along  the  shaft 
as  well  as  to  support  the  shaft  from  underneath.  This  thrust 
bearing  is  connected  to  a  worm  screw,  w^hich  is  fastened  to  the 
frame  of  the  engine,  and  is  operated  by  turning  the  hand  wheel 
H.  When  the  hand  wheel  is  so  turned  that  the  plug,  and  the 
shaft  to  which  it  is  keyed,  move  to  the  left.  Fig.  32,  the  plug  is 
set  harder  into  the  shell.  The  bearing  boxes  are  fitted  to  run 
in  machined  ways  W,  in  the  same  manner  as  the  tool  stand  on 
a  lathe. 

97.  The  necessity  for  the  thrust  bearing  is  due  to  the  fact  that 
the  plug  is  conical  instead  of  being  cyhndrical.  Since  the  surface 
of  the  plug  makes  an  angle  with  the  axis  instead  of  being  parallel 
to  it  (as  in  the  case  of  a  cylinder),  any  pressure  acting  on  the 
surface  may  be  resolved  into  two  components,  one  of  which  will 
act  parallel  to  the  axis  and  the  other  perpendicular  to  it.  The 
force  exerted  by  the  first  component  is  the  one  that  is  resisted  by 


§3  REFINING  67 

the  thrust  bearing.  The  larger  the  angle  that  an  element  of  the 
cone  makes  with  the  axis  the  greater  will  be  the  horizontal 
thrust. 

As  has  been  stated,  the  beater  is  furnished  and  dumped 
alternatel}',  a  batch  process;  but  the  Jordan  takes  its  supply 
from  a  chest,  which  is  a  supply  reservoir,  and  runs  continuously. 
The  stuff  from  the  flow  box  enters  at  A,  Fig.  32,  at  the  small  end 
of  the  cone,  and  is  discharged  at  D,  at  the  large  end.  Both  A 
and  D  are  machine  finished,  to  receive  flanged  pipe  connections. 
The  rotation  of  the  plug  at  a  relatively  high  speed,  causes  the  stuff 
to  swirl  between  it  and  the  shell,  and  the  result  of  this  swirling 
is  to  cause  the  stuff  to  be  thrown  toward  the  large  end  of  the  shell 
by  centrifugal  force.  The  stuff  passes  through  the  Jordan  in  the 
form  of  a  rather  thin  mixture,  and  it  behaves  very  much  like 
water.  It  is  under  considerably  greater  pressure  at  the  large  end 
of  the  cone,  therefore,  than  at  the  small  end,  and  the  Jordan  is 
consequently  capable  of  throwing  it  up  in  the  discharge  pipe  to  a 
considerable  height.  The  Jordan  thus  acts  somewhat  like  a 
centrifugal  pump.  Both  the  Jordan  and  the  beater  employ  the 
working  parts  to  propel  the  stock,  the  latter  by  acting  like  a 
paddle  wheel,  and  the  former  by  acting  like  a  centrifugal  pump. 

98.  A  view  of  the  plug  alone  is  shown  at  (h),  Fig.  37.  It  is 
fitted  with  bars  or  knives  K,  which  are  set  in  slots,  milled  in  the 
webs  that  support  the  roll  (plug).  These  bars  are  firmly  held  in 
place  by  wooden  strips  L,  wedged  in  between  them  when  dry. 
The  construction  is  like  that  of  the  beater  roll,  except  that  the 
Jordan  plug  is  conical.  The  large  end  of  the  cone  (plug)  is  fitted 
with  more  bars  than  the  small  end,  because  its  higher  peripheral 
speed  produces  correspondingly  higher  rate  of  wear. 

The  shell  S  is  also  fitted  on  the  inside  with  bars  similar  to  those 
of  the  plug.  Evidently,  some  means  must  be  adopted  to  prevent 
the  bars  of  the  plug  from  locking  with  those  of  the  shell;  this  is 
usually  accomplished  by  setting  the  shell  filling  so  it  slants,  first 
one  way  and  then  the  other,  in  herring  bone  style.  Jordan 
engines,  and  other  refiners,  are  sometimes  arranged  in  series 
where  more  than  one  is  provided  for  one  paper  machine.  Less 
commonly  they  are  placed  in  parallel. 

99.  Origin  of  the  Jordan. — The  Jordan  refining  engine  is  a 
development  of  an  earlier  machine  patented  by  T.  Kingsland,  of 
Franklin,  N.  J.,  in  1856.     The  Kingsland  engine  was  a  flat  disk. 


68  BEATING  AND  REFINING  §3 

with  blades  or  teeth  on  both  sides,  set  on  a  shaft,  run  in  contact 
with  two  stationary  disks,  one  on  each  side,  which  were  fitted  with 
similar  corrugations.  It  was  in  use  in  the  mills  of  T.  &  R. 
Kingsland,  and  was  said  to  have  produced  some  of  the  finest 
book  and  "flat  cap"  on  the  New  York  market.  The  intention 
of  the  inventor  was  to  devise  a  continuous  process  of  beating  that 
would  supplant  the  beater. 

In  1858,  the  conical  refining  engine  was  patented  by  Joseph 
Jordan,  a  paper-mill  superintendent,  and  Thomas  Eustice,  a 
resident  of  Hartford,  Conn.  Many  of  the  original  experiments 
leading  to  the  perfection  of  the  machine  were  carried  out  by 
Jordan  at  Cumberland  Mills,  Me.,  in  a  book-paper  mill,  operated 
by  S.  D.  Warren  &  Company,  and  the  work  was  much  facilitated 
by  the  encouragement  of  John  E.  Warren.  Jordan's  work  was 
another  attempt  to  supplant  the  beater;  but,  although  this  was 
not  accomplished,  the  work  was  so  well  done,  nevertheless,  that 
the  Jordan  refining  engine  has  come  down  to  the  present  day  with 
no  important  modifications. 

100.  Caution. — If  the  refining  engine  is  of  the  Jordan  type, 
that  is,  conical,  it  must  never  be  left  running  without  a  supply  of 
water  passing  through  it  to  cool  it;  for  it  will  heat  very  rapidly 
when  running  dry,  no  matter  how  far  out  the  plug  is  pulled.  In 
operation,  it  is  kept  cool  by  the  stuff. 


SPECIAL  TYPES  OF  REFINING  ENGINES 

101.  The  Pope  Refiner. — Although  the  Jordan  is,  by  far,  the 
most  common  single  type  of  refining  engine,  there  are  various 
modifications  of  it  in  use,  none  of  which,  however,  get  very  far 
from  the  principle  of  the  Jordan. 

Proceeding  on  the  general  design  of  the  Kingsland,  which  was 
a  flat  disk  that  revolved  on  a  horizontal  shaft,  the  Pope  refiner 
develops  a  single  face  of  contact  between  the  disk  and  the 
stationary  plate,  instead  of  the  double  contact  emploj^ed  in  the 
older  Kingsland  engine.  Further,  the  Pope  is  run  at  an  exceed- 
ingly high  speed,  and  there  is  very  little  clearance  between  the 
disk  and  the  plate.  The  setting  of  the  disk  against  the  plate 
is  as  positive  as  in  the  case  of  the  Jordan,  the  object  being  to 
prevent  any  yielding  when  small  bodies  of  material  enter  that  are 
coarser  than  the  distance  between  the  disk  and  plate,  and  to 


§3  REFINING  69 

maintain  the  fixed  plate  distance,  thus  reducing  the  size  of  such 
bodies  to  a  practically  uniform  fineness.  It  was  the  intention 
of  the  inventor  to  bring  foreign  particles  found  in  the  stock  to 
such  fine  dimensions  that  they  could  be  incorporated  in  the 
final  paper  without  detracting  from  its  appearance. 

102.  The  Claflin  Refiner. — The  Claflin  refiner  stands  between 
the  two  extremes  of  Jordan  and  Pope  refiners;  it  takes  the  form 
of  a  cone,  with  a  wide  angle,  and  it  is,  consequentl}^  very  short. 
The  purpose  of  the  Claflin  is  identical  with  that  of  the  Pope, 
and  its  design  is  like  a  very  short,  stubby  Jordan.  Its  plug  and 
shell  are  filled  in  a  manner  similar  to  the  Jordan.  In  practice, 
it  is  frequently  set  up  in  series,  a  number  of  separate  machines 
taking  the  stuff,  one  after  the  other.  This  machine  is  illustrated 
in  Section  8,  Vol.  III. 

103.  The  Marshall  Refiner. — The  Marshall  refiner  embodies 
some  of  the  features  of  both  the  Jordan  and  the  Pope,  or  Kings- 
land;  it  is  a  machine  of  the  same  size  and  weight  as  the  Jordan. 
At  the  large  end  of  the  cone,  however,  the  shell  is  faced  with 
an  annular  ring,  the  position  of  which  is  at  right  angles  to  the 
center  line  of  the  shaft;  and  the  plug  is  provided  with  a  similar 
annular  ring,  which  takes  the  form  of  a  shoulder  or  collar.  Both 
of  these  rings  are  filled  with  bars  or  knives.  The  plug  is  set  in 
hard  against  the  shell,  which  brings  this  annular  ring  in  contact 
also;  and  the  stock,  which  is  thrown  from  the  small  end  of  the 
cone  to  the  large  end,  passes  through  this  annular  ring  last, 
thus  encountering  more  working  surface  than  is  provided  in  the 
Jordan. 

104.  The  Wagg  Jordan. — In  the  wearing  down  of  the  bars  of 
the  Jordan  engine,  it  often  happens  that  much  of  the  knife  edge 
of  the  bars  becomes  dulled.  It  can  readily  be  seen  that  neither 
the  plug  nor  the  shell  will  wear  out  in  straight  lines.  Owing 
to  the  different  peripheral  speeds  at  different  cross  sections 
of  the  cone,  the  knives  tend  to  wear  in  spots;  and  the  spots  in 
which  the  wear  has  been  slower  will  tend  to  hold  the  plug  and 
shell  apart  at  the  points  where  the  wear  has  been  more  rapid. 
This  is  the  explanation  of  the  "howl,"  which  is  heard,  some- 
times, for  long  distances  from  the  mill.  The  result  on  the 
knives  is  that,  where  they  are  not  in  perfect  contact,  they  erode 
under  the  scouring  action  of  the  stuff,  and  then  become  all  the 
less  effective.     To  obviate  this,  the  Wagg  fiUing  was  devised. 


70  BEATING  AND  REFINING  §3 

This  consists  of  bars  set  in  pairs,  instead  of  being  equally  spaced, 
the  two  bars  of  a  pair  being  not  more  than  the  thickness  of  the 
steel  apart.  If  the  forward  bar  erodes,  the  follower  bar,  being 
protected  from  the  scouring,  keeps  more  nearly  to  its  original 
condition. 

105.  The  Jordan  Drive. — The  preferable  drive  for  the  Jordan 
is  a  direct-connected  induction  motor,  because  of  the  ease  of 
control  through  the  electric-power  meter,  and  also  because  this 
type  of  drive  tends  to  maintain  ahnement.  A  belt  drive,  on  the 
contrary,  tends  to  wear  the  bearings  in  the  direction  of  the  belt 
pull,  which  causes  the  plug  to  work  harder  against  one  side  of  the 
shell  than  against  the  other  side.  In  the  case  of  stoppage  of 
power  in  the  beater  room,  the  beater  rolls  must  all  be  raised  and 
the  Jordan  plugs  pulled  out,  so  that  when  the  power  is  again 
applied,  it  will  not  operate  at  first  against  a  full  load. 

106.  Conclusion. — The  beaterman's  duties  do  not  end  when 
the  stuff  he  has  prepared  passes  from  the  Jordan  engine  to  the 
machine  chest;  his  responsibilitj'-  continues  until  the  stock  is 
made  into  a  satisfactory  sheet.  This  necessitates  close  cooper- 
ation between  the  beaterman  and  the  machine  tender;  each 
ought  to  understand  the  work  of  the  other.  The  refining  engine, 
serving  largely  as  a  fitter  of  beaten  stock  for  the  paper  machine, 
comes  near  to  the  machine-tender's  sphere;  in  some  mills  the 
refiner  is  in  the  machine-tender's  charge.  Whatever  the  line 
of  division,  however,  cooperation  and  harmony  are  the  keys  to 
success. 


QUESTIONS 

(1)  Make  a  pencil  sketch  of  a  Jordan  engine  and  tell  how  it  works. 

(2)  Describe  one  type  of  refining  engine  other  than  the  Jordan. 

(3)  Should  the  beater  room  and  the  paper-machine  room  be  considered  as 
two  distinct,  separate,  and  independent  departments? 


§3  BIBLIOGRAPHY  71 

BIBLIOGRAPHY 

Beating. 

Eberhardt,  Max:  Wochbl.  Papierfabr.,  Vol.  51,  No.  47,  pp.  3319-21; 
No.  48,  pp.  3391-5,  Nov.  27,  Dec.  4,  1920. 
Beating. 

Shartle,  Charles  W. :  Year  Book,  Am.  Pulp  &  Paper  Mill  Supt.  Ass'n, 
1920,  pp.  119,  121. 
Beating. 

Stewart,  O.  C:  Paper  Trade  J.,  Vol.  72,  No.  24,  p.  30,  1921;  Paper, 
Vol.  28,  No.  15,  p.  14,  June  15,  1921;  C.  A.,i  Vol.  15,  p.  4050. 
Beating,  Concerning  the  Theory  and  Practice  of. 

Beadle,    Clayton:  Vol.    V    of    Chapters    on    Papermaking :  Crosby, 
Lockwood  and  Son,  London,   1908,  pp.   182.     German  translation 
appeared  in  1911. 
Beating,  Consumption  of  Power  in. 

Campbell,  W.  B.:  P.  P.  Mag.  Can.,  Vol.  18,  No.  43,  pp.  1087-8,  Oct.  21, 
1920. 
Beating  of  Pulp,  Notes  on  the. 

Varlot,  J.   G.:  Bull.  Ind.   J"'ab.   Papier  et  Carton,   No.   3,   pp.   40-4, 
Feb.  1,  1920;  C.  A.,  Vol.  14,  p.  1039. 
Beating  of  Paper  Pulp,  Notes  on. 

Alison,  Wm.:  World's  Paper  Trade  Rev.,  Vol.  77,  No.  11,  pp.  832, 
4,  6,  8,  858,  Mar.  17,  1922;  Paper  Makers'  Mo.  J.,  Vol.  60,  No.  4, 
pp.  133-6,  discussion,  137-9,  Apr.,  1922;  Paper  Maker,  Vol.  63,  No.  4, 
pp.  481-3,  Apr.,  1922;  Paper  Trade  J.,  Vol.  74,  No.  19,  pp.  55-7, 
May  11,  1922;  Paper,  Vol.  30,  No.  21,  pp.  7-10,  July  20,  1922;  Proc. 
Tech.  Sec,  Great  Britain,  Vol.  3,  No.  1,  pp.  40-6,  Oct.,  1922. 
Beating,  The  Degree  of,  Apparatus  for  Testing. 

Paper,  Vol.  14,  No.  5,  pp.  19-20,  Apr.  15,  1914. 
Beating,  Testing  the  Degree  of.  Apparatus  for. 

Schopper,  Alfred:  Papier-Ztg.,  Vol.  39,  pp.  642-5;  C.  A.,  Vol.  8,  p.  1502. 
Beating,  Chemical  Changes  during. 

Schwalbe,  Carl  G.:  Wochbl.  Papierfabr.,  Vol.  51,  No.  21,  pp.  1486-9, 
May  29,  1920;  Chem.-Ztg.,  Vol.  44,  p.  458,  1920,  Vol.  45,  No.  53, 
p.  1883,  1920. 
Beating,  Developments  in. 

Green,  Arthur  B.:  Paper,  Vol.  23,  No.  23,  pp.  22,  24,  Feb.  12,  1919. 
Beating  and  Beating  Engines. 

Shartle,  Charles  W.:  Paper  Trade  J.,  Vol.  75,  No.  22,  pp.  20,  22,  24,  26, 
Nov.  30,  1922;  Paper  Mill,  Vol.  46,  No.  47,  pp.  12,  28,  Dec.  2,  1922. 
Beating  of  Paper  Pulp,  the  Degree  of,  Apparatus  for  Determining. 

Skark,  E.  W.  L.:  Papierfabr.,  Vol.  11,  p.  1358;  C.  A.,  Vol.  8,  p.  1205. 
Beating,  the  Degree  of.  Can  the  Water  Retained  in  a  Pulp  Serve  as   a 
Criterion  for. 
Skark,  E.  W.  L.:  Papierfabr.,  Vol.  11,  pp.  1381-9,  1417-25;  C.  A., 
Vol.  8,  p.  1502. 

'  C.  A.  refers  to  Chemical  .\bstracts,  published  semi-monthly  by  the  American  Chemical 
Society;  J.  S.  C.  I.  means  Journal  Society  of  Chemical  Industry;  P.  P.  Mag.  Can.  means 
Pulp  and  Paper  Magazine  of  Canada. 


72  BEATING  AND  REFINING  §3 

Beating,  Determining  the  Degree  of. 

Skark,  E.  W.  L. :  Papierfabr.,  Vol.  19,  No.  23,  pp.  569-76,  June  10,  1921. 
Beating  of  Paper  Pulp,  New  Process  for  Determining  the  Degree  of. 

Skark,  E.  W.  L.:  Papierfabr.,  Spec.  No.,   1914,  pp.  87-92,  Vol.   12, 
pp.  743-7;  C.  A.,  Vol.  8,  p.  3117;  Papierfabr.,  Vol.  20,  No.  25,  pp. 
845-52,  June  25,  1922;  Paper  Trade  J.,  Vol.  75,  No.  21,  pp.  53-5, 
Nov.  23,  1922. 
Beating  Tests. 

Sutermeister,   E.:  Paper,   Vol.   23,  No.    14,  pp.    11-3,   Dec.    11,  1918; 
P.  P.  Mag.  Can.,  Vol.  17,  No.  3,  pp.  47-9,  Jan.  16,  1919;  C.  A., 
Vol.  13,  p.  260. 
Beating  Tests  for  Paperinaking  Fibers. 

Sutermeister,  E.:  Paper,   Vol.   17,   No.  9,   pp.   11-8,   Nov.    10,    1915; 
C.  A.,  Vol.  10,  p.  525. 
Beating,  Sizing,  and  Loading. 

Teren,  George:  Paper  Ind.,  Vol.  3,  pp.  710-13,1921;  C.  A.,  Vol.  15,  p.  4050. 
Beating,  Theory  and  Practice  of,  Remarks  on. 

Beadle,  Clayton:  Papierfabr.,  Vol.   10,  No.  49,  pp.   1393-9,  Dec.    6, 
1912. 
Beating,  Power  Consumption  in. 

Beadle,  Clayton:  Paper,  Vol.  10,  No.  1,  pp.  15-18,  34,  Dec.  18,  1912. 
Beating,  Today  and  Tomorrow. 

Campbell,  W.  B.:  Paper,  Vol.  27,  No.  25,  pp.  25-6,  32,  Feb.  23,  1921; 
Paper  Maker,  Vol.  62,  No.   1,  pp.  37,  39,  July,  1921;  P.  P.  Mag. 
Can.,  Vol.  19,  No.  3,  pp.  65-67,  1921. 
Beating  and  Hydration. 

Cyster,  F.:  World's  Paper  Trade  Rev.,  July  16,  1915;  Paper,  Vol.   16, 
No.  22,  pp.  13-4,  Aug.  11,  1915;  C.  A.,  Vol.  9,  p.  3129. 
Beating,  Some  Methods  for  the  Study  of. 

Green,  Arthur  B.:  Paper,  Vol.  17,  No.  24,  pp.  21-8,  1916;  C.  A.,  Vol. 
10,  p.  1432. 
Beating,  Viscosity  Principle  in. 

Green,  Arthur  B.:  Paper,  Vol.  21,  No.  7,  pp.  17,  34,  Oct.  24,  1917. 
Beating  of  Sulphite  Pulp,  Experiments  in  the. 

Kress,  Otto,  and  McNaughton,  G.  C. :  Paper,  Vol.  20,  No.  17,  pp.  13-7, 
July  4,  1917;  C.  A.,  Vol.  11,  p.  2542. 
Beating  Problems. 

Leicester,  Sheldon:  World's  Paper  Trade  Rev.,  Vol.  77,  No.  14,   pp. 
1066-8,  Apr.  7,  1922. 
Beating,  the  Time  of.  Effect  of  Certain  Chemicals  on. 

Mansfield,  E.  K,  and  Stephenson,  J.  N.:  P.  P.  Mag.  Can.,  Vol.  14, 
No.    19,   pp.   325-7,  Oct.  1,  1916;  Paper,  Vol.  19,  No.  8,  pp.  17-9, 
Nov.  1,  1916;  C.  A.,  Vol.  11,  p.  887. 
Beating  Conditions  as  Affected  by  the  Temperature  of  the  Water. 
Hatch,  R.  S.:  Paper,  Vol.  19,  No.  20,  pp.  18-9,  Jan.  24,  1917. 
Beating  Engine,  Theory  of  the. 

Haussner,   Alfred:  Papierfabr.   Spec.    No.,    1913,   pp.   46-51;   C.    A., 
Vol.  7,  p.  3839. 
Beating  Requirements  for  Cigarette  Paper  (see  Cigarette  Paper). 


§3  BIBLIOGRAPHY  73 

Beater,  The  Story  of  the. 

Wheelwright,  Wm.  Bond:  Alfelco  Facts,  Vol.  1,  No.  3,  pp.  5-14,  1922. 
Beater,  The  Action  of  the,  in  Papermaking. 

Smith,  Sigurd:  Paper  Trade  J.,  Vol.  75,  No.  26,  pp.  47-8,  Dec.  28,  1922; 
Vol.  76,  No.  1,  pp.  49-53,  Jan.  4,  1923;  World's  Paper  Trade  Rev., 
Vol.  78,  No.  21,  pp.  1705-6,  1708,  1710,  No.  22,  pp.  1810,  12,  14, 
16,  Nov.  24,  Dec.  1,  1922. 
Beater,  The,  in  Great  Britain  from  the  Engineering  Point  of  View. 

Nuttall,  T.  D.:  Proc.  Tech.  Sec,  Great  Britain,  Vol.  1,  No.  2,  pp.  180-5, 
Aug.,    1921;    Paper  Trade  J.,   Vol.   74,  No.   6,  pp.   48-9,  Feb.  9, 
1922- 
Beater,  New  Niagara,  Development  of  the. 

Burns,  W.  H.:  Paper,  Vol.  27,  No.  19,  pp.  13-4,  Jan.  12,  1922. 
Beater  Consistency  Changes,  A  Study  of. 

Gesell,  W.  H.,  and  Minor,  Jessie  E.:  Paper,  Vol.  24,  pp.  443-7,  1919; 
C.  A.,  Vol.  13,  p.  1765. 
Beater  Furnish,  Report  of  Committee  on. 

Miller,  H.  F.:  Paper  Trade  J.,  Vol.  74,  No.  23,  pp.  48-50,  June  8,  1922; 
Paper,   Vol.   30,   No.   20,  pp.  7-10,  July  19,  1922;  Paper  Mill,  Vol. 
45,  No.  21,  pp.  14,  16,  78,  June  3,  1922. 
Beater  Sizing,  Function  of  Starch  in. 

Traquair,  John:  Paper,  Vol.  21,  No.  23,  pp.  68,  70,  Feb.  13,  1918. 
Beater  Room,  Management  in  the. 

Green,  Arthur  B.:  Paper,  Vol.  19,  No.  23,  pp.  19,  20,  22,  24,  26,  28,  30, 
32,  34,  36,  38,  40,  54,  Feb.  14,  1917. 
Beaters,  Notes  on  the  Efficiency  of. 

Schhck,  Leo:  Paper,  Vol.  15,  No.  14,  pp.  18-21,  38,  Dec.    16,  1914; 
P.  P.  Mag.  Can.,  Vol.  12,  No.  22,  pp.  647-52,  Nov.  15,  1914. 
Beaters,  Power  Consumption  of,  Calculating  the. 

Bouvier,  F.  M.:  Moniteur  de  la  Papeterie  Francaise,  Vol.  52,  pp.  788- 
790,  Dec.  15,  1922;  Paper  Trade  J.,  Vol.  74,  No.  13,  pp.  4.5-6,  Mar.  30, 
1922;  Zellstoff.  u.  Papier,  Vol.  2,  No.  2,  pp.  37-40,  Feb.,  1922. 
Beaters,  Roll  Pressure  of.  Standardization  and  Measurement  of  the. 

Muller,  :  Zellstoff  u.  Papier,  Vol.  2,  No.  1,  p.  22,  Jan.,  1922; 

P.  P.  Mag.  Can.,  Vol.  20,  p.  564,  July  6,  1922. 
Beater?  Why  is  a. 

Schlick,  Leo:  P.  P.  Mag.  Can.,  Vol.  17,  pp.  1024-5. 
Cellulose,  Colloidal  Properties  of. 

Minor,  Jessie  E.:  Paper,  Vol.  25,  No.  14,  pp.  700-3,  1919;  C.  A.,  Vol.  14, 
p.  344. 
Cellulose,  The  Constitution  of. 

Gesell,  W.  H.,  and  Minor,  Jessie  E.:  Paper,  Vol.  24,  pp.  527-9,  1919; 
C.  A.,  Vol.  13,  p.  1925. 
Cellulose,  Cotton,  Action  of  Water  and  Alkali  upon. 

Schwalbe,  Carl  G.,  and  Robinoff,  Michael:  Z.  angew.  Chem.,  Vol.  24, 
pp.  256-8;  C.  A.,  Vol.  5,  p.  1838. 
Cellulose,  Reactions  of. 

Seibert,  Florence  B.,  and  Minor,  Jessie  E. :  Paper,  Vol.  24,  No.  23,  pp. 
1007-12,  Aug.  13,  1919;  C.  A.,  Vol.  13,  p.  2440. 


74  BEATING  AND  REFINING  §3 

Cellulose,  Contribution  to  the  Knowledge  of.     Hydrocellulose. 

Jentgen,  H.:  Z.  angew.  Chem.,  Vol.  23,  pp.  1541-6;  Vol.  24,  pp.  11-2; 
C.  A.,  Vol.  5,  pp.  1187,  1677. 
Cellulose  Hydrate — A  Contril)ution  to  the  Knowledge  of  the  Decomposition 
of  Mordanting  Salts  by  Cellulose. 
Schwalbe,  Carl  G.:  Z.   angew.  Chem.,   Vol.   .32,   I,  pp.   355-7,    1919; 
C.  A.,  Vol.  14,  p.  1437. 
Cellulose,  Hydration  of,  During  Beating. 

Briggs,  J.  F.:  Papierfabr.,  Special  No.,  1910,  pp.  46-9. 
Cellulose  Mucilage. 

Minor,  Jessie  E.:  J.  Ind.  Eng.  Chem.,  Vol.  13,  pp.  131-3,  1921;  C.  A., 
Vol.  15,  p.  1212. 
Cellulose  Mucilage,  Study  of. 

Schwalbe,  Carl,  and  Becker,  Ernst:  Z.  angew.  Chem.,  Vol.  32,  I,  pp. 
265-9,  1919;  Vol.  33,  I,  pp.  57-8,  1920;  C.  A.,  Vol.  14,  pp.  837.  3790, 
3528. 
Chemistry,  Fundamental,  in  Paper  Making,  with  a  Note  on  the  Chemistry 
of  the  Beating  Process. 
MacDonald,  J.  L.  A.:  World's  Paper  Trade  Rev.,  Vol.  76,  Nos.  13,  14, 
1921;  Chem.  Trade  J.,  Vol.  69,  pp.  397-9,  1921;  P.  P.  Mag.  Can., 
Vol.  19,  No.  42,  1067-9,  Oct.  20,  1921;  Paper  Mill,  Vol.  44,  No.  46, 
pp.  18,  20,  90,  Nov.  5,  1921;  Proc.  Tech.  Sec,  Great  Britain,  Vol.  2, 
No.  2,  pp.  132-42,  Mar.,  1922. 
Cigarette  Paper,  Beating  Requirements  for. 

Paper,  Vol.  23,  No.  20,  pp.  11-3,  Jan.  22,  1919. 
Colloid  Chemistry  and  Papermaking. 

Rohland,  P.:  Wochbl.  Papierfabr.,  Vol.  44,  pp.  2075-7;  Paper  Maker, 
Vol.  46,  No.  5,  p.  762,  Nov.,  1913;  Paper,  Vol.  12,  No.  11,  p.   21, 
Aug.  27,  1913;  P.  P.  Mag.  Can.,  Vol.  12,  No.  2,  p.  45,  Jan.  15,  1914. 
Colloidal  Chemistry  as  Applied  to  the  Paper  Industry. 

Darrah,  W.  A.:  Paper  Ind.,  Vol.  1,  No.  12,  pp.  1137-41,  1160-9,  Mar., 
1920. 
Colloidal  Chemistry  in  Papermaking,  The  Function  of. 

DeCew,  Judson  A.:  J.  S.  C.  I.,  Vol.  36,  pp.  357-9,  1917;  Paper,  Vol.  20, 
No.  11,  pp.  13-5,  May  23,  1917;  Paper  Maker,  Int.  No.,  1916-1917, 
pp.  44-5,  47;  Sci.  Am.  Sup.,  Vol.  84,  pp.  191-2,  Sept.  22,  1917;  C.  A., 
Vol.  11,  p.  1901. 
Colloidal  Chemistry  in  Papermaking. 

Bovard,  W.  M.:  Paper,  Vol.  22,  No.  3,  pp.  11-6;  P.  P.  Mag.  Can.,  Vol. 
16,   pp.   729-31,  740,  751,  766,   Aug.  15,  22,  1918;  C.  A.,  Vol.  12, 
p.  1251. 
Consistency  of  Stock  and  White  Water,  Relation  between  the,  on  Paper 
Machines. 
Trimbey,    Edward   J.:  P.    P.  Mag.  Can.,  Vol.  13,  No.  2,  pp.    34-7, 
Jan.  15,  1915. 
Density  of  Pulp  and  its  Relation  to  the  Beater. 

Paper  Trade  J.,  Vol.  60,  No.  10,  p.  52,  Mar.  11,  1915;  P.  P.  Mag.  Can., 
Vol.  13,  No.  7,  p.  206,  Apr.  1,  1915;  Paper  Maker,  Vol.  50,  No.  2, 
p.  188,  Aug.,  1915. 


§3  BIBLIOGRAPHY  75 

Freeness  Testing  of  Pulp. 

Williams,  F.  M.:  Paper  Trade  J.,  Vol.  74,  No.  23,  pp.  43-4,  June  8, 
1922;  Paper  Mill,  Vol.  45,  No.  21,  pp.  26-7,  June  3,  1922;  Paper,  Vol. 
30,  No.  19,  pp.  10-11,  July  12,  1922;  World's  Paper  Trade  Rev.,  Vol. 
78,  No.  3,  p.  206,  July  21,  1922. 
[Freeness  Tester]  Apparatus  for  Determining  the  "Freeness"  of  Paper  Stock. 
Ivirchner,  E.:  Wochbl.  Papierfabr.,  Vol.  44,  pp.  3694-7;  C.  A.,  Vol.  8, 
p.  246. 
Furnish  to  Beaters,  Proper  Order  of  Adding. 

Sunderland,  A.  E.:  Paper,  Vol.  20,   No.  4,  pp.   13-6,  Apr.  4,   1917; 
C.  A.,  Vol.  11,  p.  1544. 
"Greasy"  or  "Free"  Stuflf. 

Ivirchner,  E.:  Wochbl.  Papierfabr.,  Vol.  44.  pp.  3517-20;  C.  A.,  Vol.  8, 
p.  246. 
Hazards,  Beater-Room. 

Walker,  Charles:  Paper  Trade  J.,  Vol.  73,  No.  14,  p.  46,  Oct.  6,  1921; 
Paper,  Vol.  29,  No.  6,  pp.  9-10,  Oct.  12,  1921;  P.  P.  Mag.  Can., 
Vol.  20,  No.  16,  pp.  317-8,  Apr.  20,  1922;  World's  Paper  Trade  Rev., 
Vol.  77,  No.  24,  p.  1876,  June  16,  1922. 
Heating  of  Stuff  in  the  Beater. 

World's  Paper  Trade  Rev.,  Vol.  78,  No.  2,  p.  100,  July  14,  1922;  Paper 
Makers'  Mo.  J.,  Vol.  60,  No.  1,  p.  7,  Jan.  16,  1922. 
Hollander,  The  Action  of  the,  upon  Pulp. 

Smith,  Sigurd:  Papierfabr.,  Vol.  18,  No.  32,  pp.  591-4,  Aug.  6,  1920. 
Hollander,  The  Beating  Process  in  the. 

Sellergren,  G.:  Papierfabr.,  Vol.  18,  No.  32,  pp.  59i-6,  Aug.  6,  1920. 
Hollander,  Development  of  the. 

Blau,  Ernst:  Papierfabr.,  Vol.  19,  No.  28,  pp.  721-7,  No.  29,  pp.  753-7, 
July  15,  22,  1922. 
Hollander,  Rational  Theory  of  the. 

Smith,  Sigurd:  Papierfabr.,  Vols.   18,   19,   1920,   1921.  '  Reprinted  as 
"Die  Rationelle  Theorie  des  GanzzeughoUanders,"  by  Otto  Eisner 
Verlagsgesellschaft,  1922,  192  pp.     Arrangements  have  been  made  by 
the  Tech.  Ass'n  of  Great  Britain  to  translate  the  work  into  English. 
Hollanders. 

Panaitopol,  Geo.:  Wochbl.  Papierfabr.,  Vol.  38,  pp.  3736-40,    Nov., 
1907;  C.  A.,  Vol.  2,  p.  586. 
Hollanders  and  their  Po\yer  Consumption. 

Pfarr,  A.:  Wochbl.  Papierfabr.,  Vol.  38,  pp.  3032-9,  3111-6,  3185-90, 
3261-5,  1907. 
Hollanders,  The  Theory  of. 

Krchner,  E.:  Wochbl.  Papierfabr.,  Vol.  38,  pp.  3983-6,  4062-7,   Dec. 
14,  1907. 
Hollander  Beater,  Consideration  of  the. 

Kirchner,  E.:  Wochbl.  Papierfabr.,  Vol.  49,  pp.  282-3,  423-4;   C.  A., 
Vol.  14,  p.  122. 
Hollander  Drives  and  Self-Regulation  of  the  Hollander. 

Stiel,  Wilhelm:  Wochbl.  Papierfabr.,  Vol.  51,  No.  14,  pp.  993-5;  No.  15, 
pp.  1066-9,  Apr.  10,  17,  1920. 


76  BEATING  AND  REFINING  §3 

Hollander  Considerations. 

Haussner,  Alfred:  Wochbl.  Papierfabr.,  Vol.  52,  No.  21,  pp.   1628-33, 
No.  27,  pp.  2176-80,  No.  31,  pp.  2495-8,  No.  33,  pp.  2661-4,  No.  39, 
pp.  3179-83,  No.  44,  pp.  3605-7,  No.  48,  pp.  3965-7,  No.  49,  pp. 
4049-52,  1921. 
Hollander  Construction  and  its  Influence  upon  the  Beating  Effect. 

Kirchner,  E.:  Wochbl.  Papierfabr.,  Vol.  51,  No.  23,  pp.  1626-8,  No.  25, 
pp.  1770-2,  June  12,  23,  1920. 
Hollander  Rolls.     Speed  of  Movement  of  the  Pulp  and  Beating  EflBcicncy 
of  the  Rolls. 
Piesslinger,  Fritz:  Wochbl.  Papierfabr.,  Vol.  38,  pp.  3507-10,  3585-8, 
Oct.  26,  Nov.  2,  1907;  C.  A.,  Vol.  2,  p.  585. 
Hj'drating  Machinery  for  the  Paper  Mill. 

Bidwell,  George  L.:  Tech.  Assoc.  Papers,  Vol.  5,  No.  1,  pp.  7-8,  1922; 
Paper  Trade  J.,  Vol.  74,  No.  15,  pp.  191,  193,  Apr.  13,  1922;  Paper 
Mill,  Vol.  45,  No.  14,  p.  .54,  Apr.  15,  1922;  Paper,  Vol.  30,  No.  7, 
pp.  53-4,  56,  Apr.  19,  1922;  Paper  Ind.,  Vol.  4,  No.  1,  pp.  78-80, 
Apr.,  1922;  Boxboard,  Vol.  1,  No.  5,  pp.  16-18,  May,  1922. 
Hydration,  Effect  of,  on  the  Retention  of  Stuff". 

Cyster,  F.:  Paper  Making,  Vol.  34,  pp.  487-9;  Paper,  Vol.  15,  No.  15, 
pp.  17,  38,  Dec.  23,  1914;  Paper  Trade  J.,  Vol.  59,  No.  26,  p.  52, 
Dec.  31,  1914;  C.  A.,  Vol.  9,  p.  1843. 
Hydration  in  Papermaking  Processes. 

Beadle,  Clayton,  and  Stevens,  H.  P.:  J.  S.  C.  I.,  Vol.  32,  pp.   217-8; 
P.  P.  Mag.  Can.,  Vol.  11,  No.  9,  pp.  295-6,  May  1,  1913;  Paper,  Vol. 
11,  No.  5.  pp.  19-20,  Apr.  16,  1913;  C.  A.,  Vol.  7,  p.  2305. 
Hydration  of  Cellulose  During  Beating  (see  Cellulose). 
Hydration  of  Pulp,  Chemical. 

MacKay,  Alfred:  Paper,  Vol.  29,  No.  16,  pp.  7-10,  Dec.  21,  1921. 
Hydration  of  Sulphite  and  Esparto  Pulps. 

Papeterie,  Vol.  43,  pp.  146-9,  1921;  C.  A.,  Vol.  15,  p.  1620. 
Hydrocellulose. 

Schwalbe,  Carl  G.:  Z.  angew.  Chem.,  Vol.  23,  pp.  2030-1;  Vol.  24,  p.  12; 
C.  A.,  Vol.  5,  pp.  1187,  1677. 
Length  of  Cotton  and  Linen  Fibers,  Diminution  in,  During  the  Preparation 
of  Stuff  for  the  Manufacture  of  Paper. 
Beadle,  Clayton,  and  Stevens,  H.  P. :  Chem.  News,  Vol.  96,  pp.  139-40, 
Sept.,  1907;  C.  A.,  Vol.  2,  p.  586. 
Mucilage  of  Parchment  Paper  Pulps. 

Seibert,  Florence  B.,  and  Minor,  Jessie  E.:  P.  P.  Mag.  Can.,  Vol.   18, 
pp.  930-42,  1920;  C.  A.,  Vol.  15,  p.  2183. 
Power  Consumption  of  Beaters. 

Schulte,  H.:  Zentr.  Oesterr-ungar.  Papierind.,  Vol.  28,  p.  871,    1914; 
Paper,  Vol.  15,  No.  24,  pp.  15-16,  Jan.  27,  1915;  C.  A.,  Vol.  9,  p.  1114. 
Power  Consumption  of  Beaters,  Calculating  the  (see  Beaters). 
Power  Consumption,  Influence  of,  during  Beating  on  the  Strength  and  Ash 
Content  of  Paper. 
Fotieff,  S.:  Papierfabr.,  Vol.  11,  pp.  1263-7;  C.  A.,  Vol.  8,  p.  1502. 


§3  BIBLIOGRAPHY  77 

Power  Consumption  when  Beating  Half-Stuff  and  Whole  Stuff. 

Rehn,  Arnold:  Papierfabr.,  Spec.  No.,  1912,  pp.  68-81,  No.  37,  pp. 
1051-8.  No.  38,  pp.  1079-83,  No.  39,  pp.  1106-9,  S-pt.  13-27,  1922; 
C.  A.,  Vol.  6,  p.  2526,  Vol.  7,  pp.  889,  2855;  P.  P.  Mag.  Can.,  Vol.  11, 
No.  19,  pp.  651-7;  No.  20,  pp.  680-5,  Oct.  1,  15,  1913,  No.  21,  pp! 
709-13,  Nov.  1,  1913. 
Safety  in  the  Beater  Room. 

Drumb,  Frank  A.:  Paper  Ind.,  Vol.  4,  No.  5,  pp.  652-5,  Aug.,   1922. 
Slowness  Tester,  Green's. 

P.  P.  Mag.  Can.,  Vol.  20,  No.  36,  p.  765,  Sept.  7,  1922. 
Soda  Consumption  and  Time  of  Beating,  Influence  of,  on  Paper. 

Beadle,  Clayton,  and  Stevens,  H.  P.:  Paper,  Vol.  11,  No.  2,  pp.  18-22, 
Mar.  26,  1913;  P.  P.  Mag.  Can.,  Vol.  11,  No.  8,  pp.  256-9. 
Temperature,  The  Influence  of,  on  the  Speed  with  which  Water  Drains  from 
Paper  Pulp. 
Smith,  Sigurd:  Papierfabr.,  Vol.  17,  pp.  1121-3,  1919;  C,  A.,  Vol    14 
p.  222. 
Testing  the  Condition  of  Paper  Stuff. 

Klemm,   Paul:  Wochbl.   Papierfabr.,   Vol.   38,   pp.   3822-32,   3986-7, 
1907;  C.  A.,  Vol.  2,  p.  588. 
Tester,  Schubert's,  for  the  Degree  of  Beating. 

Zellstoff  u.  Papier,  Vol.  1,  pp.  21-3,  1921;  C.  A.,  Vol.  15,  p.  3395. 


BEATING  AND  REFINING 


EXAMINATION  QUESTIONS 

(1)  What  is  the  purpose  of  beating? 

(2)  Name  the  principal  parts  of  the  modern  Hollander. 

(3)  How  is  the  batch  sj^stem  of  operating  beaters  converted 
into  continuous  operation  for  the  paper  machine? 

(4)  Make  a  pencil  sketch  of  a  pulp  mixer  and  explain  how  it 
works. 

(5)  (a)  What  should  be  the  size  of  a  stuff  chest?  (6)  What  are 
the  principal  requirements  of  a  good  stuff  chest? 

(6)  If  the  stuff  in  a  Jordan  chest  is  of  3%  consistency  and  its 
weight  is  taken  as  62.5  lb.  per  cu.  ft.,  at  how  many  revolutions  per 
minute  must  the  crank  shaft  of  a  single-acting,  simplex  pump 
turn  to  throw  1  ton  (2000  lb.)  of  bone-dry  stock  per  hour,  allow- 
ing 10%  for  leakage  in  the  pump?  The  diameter  of  the  pump 
cyhnder  is  8  in.  and  its  stroke  is  12  in.  Ans.  63  r.p.m. 

(7)  (a)  How  can  uniformity  of  consistency  be  obtained  when 
furnishing  beaters?  (b)  Of  what  benefit  is  it  to  secure  this 
uniformity? 

(8)  What  should  be  done  with  the  beaters  and  Jordans  in  case 
of  interruption  of  power? 

(9)  State  the  usual  order  of  furnishing  the  beater. 

(10)  Define:  (a)  bed-plate;  (6)  back-fall;  (c)  lighter;  (d)  free 
stock;  (e)  slow  stock;  (/)  hydration. 

(11)  Describe  some  changes  in  the  fiber  as  the  beating 
proceeds. 

(12)  Do  you  think  anj'  type  of  refiner  that  is  described  in  this 
Section  can  perform  all  the  functions  of  a  beater?  Explain  your 
answer. 

(13)  A  certain  beater  has  a  capacity  of  420  cu.  ft.  (a)  If  filled 
with  stuff  at  5  %  consistency,  how  many  pounds  of  bone-dry  fiber 
§3  79 


so  BEATING  AND  REFINING  §3 

will  it  hold?  (6)  How  many  pounds  of  wet  laps  of  pulp,  30% 
bone  dry,  must  be  used  to  fill  this  beater  to  the  above  consistency? 
(c)  How  many  pounds  of  water  must  be  added  with  the  laps  of 
pulp?  Assume  that  both  the  stuff  and  the  wet  laps  weigh  62.5 
lb.  per  cu.  ft.  f  (a)  1181.25  lb. 

Ans.      \  (b)  3937.5    lb. 
i  (c)  22312.5  1b. 


SECTION  4 

LOADING  AND  ENGINE 
SIZING 


(PART  1) 

By  Ross  Campbell,  B.  S. 


LOADING 


FILLERS 


1.  Why  Paper  Contains  Substances  Other  than  Fiber. — Fiber 

is,  of  course,  the  chief  constituent  of  all  paper.  If,  however, 
fiber  were  the  only  substance  entering  into  its  composition,  the 
usefulness  of  paper  would  be  very  much  restricted,  as  the  sheet 
would  be  soft,  of  a  yellowish  color,  and  could  not  be  written  on 
with  a  pen;  printing  ink  would  not  "take  well"  on  it.  If  the 
sheet  were  thin,  it  would  be  so  transparent  that  words  written  or 
printed  on  one  side  of  it  could  be  read  through  the  sheet.  An 
example  of  paper  made  of  especially  pure  fiber  is  filter  paper. 
It  is  necessary,  then,  to  add  many  other  substances  to  the  fiber 
to  produce  paper  suited  to  the  many  uses  to  which  it  is  put;  and 
among  these  substances  are  sizing,  coloring,  and  fillers  or  loading. 
(Loading  properly  means  the  adding  of  a  filler,  but  the  term  is 
also  applied  to  the  substances  added.)  If  a  sheet  were  made  in 
the  same  manner  as  the  average  book  paper,  but  without  adding 
a  filler,  it  would  be  found  to  be  more  translucent;  i.e.,  the  printed 
letter  would  show  through,  and  it  would  not,  as  a  rule,  take  fine 
line  cuts  as  clearly  as  it  would  if  a  filler  had  been  added.  The 
principal  features  in  connection  with  the  use  of  fillers  will  be 
treated  in  this  Section. 
§4  1 


2  LOADING  AND  ENGINE  SIZING  §4 

2.  What  Fillers  Are  and  Why  They  are  Used. — All  fillers  are 
mineral  substances:  they  may  be  (a)  a  natural  product,  as  talc, 
which  is  merely  a  particular  kind  of  rock,  properly  ground  and 
bolted  (screened);  or  (6)  a  manufactured  article,  as  crown  filler. 
Many  substances  used  as  fillers  are  also  used  for  coating  paper 
and  boards;  this  latter  use  is  not  considered  in  the  Section. 

Although  it  usually  has  the  effect  of  making  paper  less  costly, 
filler  is  not,  in  general,  added  to  paper  for  the  purpose  of  cheapen- 
ing it;  its  primary  purpose  is  to  secure  qualities  not  otherwise 
obtainable.  The  largest  quantities  of  filler  are  probably  used  in 
book  papers,  where  it  is  desired  to  produce  an  opaque  sheet  that 
has  good  ink-absorbing  properties  and  a  very  smooth  and  even 
surface  for  taking  haK-tone  cuts;  in  this  case,  the  presence  of 
filler  improves  the  surface,  especially  when  the  paper  is  super- 
calendered.  The  filler  occupies  the  spaces  between  the  fibers, 
so  that  the  whole  surface  gets  approximately  the  same  pressure 
and  friction  from  the  calender.  In  papers  of  this  kind,  the 
amounts  of  filler  added  to  the  beaters  vary  from  5%  to  40%  for 
clay,  and  5%  to  20%  for  talc  and  agalite;  the  average  is  10%  to 
15%  for  all  kinds  of  fillers.  In  the  case  of  papeteries,  where  a 
ver}'-  high  color  and  delicate  tints  are  frequently  desired,  a  filHng 
or  loading  substance,  as  crown  filler,  having  a  higher  color  than 
the  stock,  is  of  very  great  use.  Many  special  industrial  papers 
must  be  loaded,  some  of  them  very  heavily,  in  order  to  fulfill 
their  special  requirements;  as  an  example,  stereo-matrix  board 
may  be  mentioned.  In  practice,  this  latter  is  built  up  by  pasting 
several  sheets  together,  the  whole  being  then  covered  by  a  special 
and  very  tough  tissue  paper.  On  this,  an  impression  is  made 
from  type  already  cast  by  the  linotype  or  otherwise  composed. 
After  the  impression  is  made,  the  matrix,  as  it  is  then  called,  is 
used  as  a  mold  for  casting  type  to  fit  the  rotary  printing  presses. 
In  order  to  take  a  good  impression  without  breaking,  and  to 
give  a  good  cast,  it  is  requisite  that  the  board  be  properly 
loaded. 

In  general,  the  presence  of  filler  tends  to  decrease  the  strength 
and  size-fastness  of  a  sheet;  but  this  effect  is  not  sufficiently 
marked  to  be  of  commercial  importance,  unless  the  amount  of 
filler  used  be  large.  If  the  strength  of  paper  is  specified,  proper 
selection  and  treatment  of  the  fiber  must  be  observed.  Size- 
fastness  has  not  the  same  significance  in  printing  papers  as  in 
writings,  because  printing  inks  have  an  oily  medium. 


§4 


LOADING 


3 


3.  Names  of  Fillers. — There  are  comparatively  few  fillers  in 
use  in  the  paper  industry  in  America.  Those  commonly  met 
with  are:  clay,  talc,  agalite,  crown  filler,  and  pearl  filler.  For 
special  purposes,  small  quantities  of  barytes  (barium  sulphate), 
satiii  white,  or  chalk  are  used.  The  following  table  gives  the 
name,  chemical  formula,  approximate  composition,  and  principal 
uses  for  fillers  commonly  used  in  the  paper  industry : 


PAPER  FILLERS 


Name 

„          ,                  Analysis                          ., 
Formula           ,                    ..  s                     Lse 
(approximate) 

Natural  Fillers: 

H4Al2Si209 

46%  SiOj 
40%  AI2O3 
14  %  H2O 

(1)  Book 

(2)  Coating 

(3)  Lower-grade  writ- 
ings 

2.  Talc 

2Mg3(Si03)4 

63  %  Si02 

32%  MgO 

5%  H2O 

(1)  Lower-grade  writ- 

(2)  Book 

3.  Agalite 

H2Mgj(Si03)4 

63%  Si02 

32%  MgO 

5%  H2O 

Same  as  talc 

4.  Pearl  filler  (terra  alba) CaS0< 

(1 )  Lower-grade  writ- 

ings 

1 
5.  Barytes  (heavy  spar) j  BaSOi 

(1)  Coatings 
(2)Litho     papers 
(chiefly  abroad) 
(3)  Photographic 

6.  Chalk CaCOa 

(1)  Cigarette 

Artificial  Fillers: 

1.  Crown  filler  (pearl  harden-      CaSOi-2H50 

(1)  Writings 

(2)  Superfines 

(1)  Cigarette 

3.  Blanc   fixe    (artificial   heavy 

BaS04 

(1)  Coating 
(2)Litho     papers 
(chiefly  abroad) 
(3)  Photographic 

3CaS04 
+  Ah(OH)a 

I 

29  %  SOi 
13%  khOz 
39  %  CaO 
19  %     loss    on 
ignition 

(1)  Coating 

LOADING  AND  ENGINE  SIZING  §4 

SOURCES  AND  CHARACTER  OF  FILLERS 


CLAY 


4.  How  Produced. — Clay,  known  also  as  kaolin  and  china 
clay,  is  formed  by  the  weathering  or  gradual  disintegration  of  a 
certain  kind  of  rock  called  feldspar;  it  is  one  of  the  most  widely 
distributed  of  our  minerals.  In  England,  clay  is  mined  by  first 
removing  the  dirt,  or  overburden.  A  pit  is  dug  in  the  center  of 
this  cleared  space,  and  a  wooden  pipe  is  sunk  in  the  bottom  of  the 
pit  to  a  depth  of  about  100  feet.  The  bottom  of  this  pipe  is 
connected  to  pumping  machinery.  The  clay  is  washed  down 
the  sides  of  the  pit,  around  the  pipe,  by  means  of  streams  of 
water.  The  resulting  water  and  claj''  mixture  enters  the  central 
pipe  by  holes  left  for  the  purpose.  It  is  then  pumped  through 
long  troughs,  where  the  heavier  impurities  settle  out.  From  the 
troughs,  it  flows  to  setthng  tanks,  where  the  water  is  drawn  oflf 
as  the  clay  settles,  until  the  remaining  mass  is  pasty.  This  is 
dug  out  and  is  taken  to  the  drj-ing  shed.  After  drying,  the  clay 
is  ready  for  shipment. 

In  America,  the  first  steps  in  mining  clay  are  different,  two 
methods  being  used:  (a)  the  open-cut  method,  in  which  the 
overburden  is  first  removed,  and  the  clay  is  dug  out  and  shoveled 
into  small  cars;  (6)  the  shaft  method,  in  which  a  shaft,  usually 
vertical,  is  sunk,  and  the  clay  is  mined  and  hoisted  to  the  surface. 

Regardless  of  the  method  emploj^ed  in  mining,  the  clay  is  then 
broken  up  in  water;  after  which,  it  flows  through  a  sand  box  and 
sand  and  mica  troughs,  to  remove  the  heavy  impurities.  It  is 
then  screened  through  either  stationary  or  shaking  screens;  after 
which,  it  is  filter-pressed  and  dried.  This  wet  method  has  been 
displaced  by  a  dry  method  in  some  mines.  In  the  latter  case, 
the  clay  is  taken  direct  from  the  mine  to  the  drying  shed.  As 
soon  as  it  is  sufficiently  dried,  it  is  ground,  and  is  then  freed  from 
heavy  impurities  by  air  separation.     (See  Fig.  3.) 

Much  of  the  southern  sedimentary  clay  is  not  purified.  It  is 
mined,  dried  in  open  sheds  by  exposure  to  the  air,  and  is  shipped 
as  crude  domestic  cla}'. 

5.  Impurities  in  Clay. — As  would  naturally  be  expected  from 
its  origin,  the  chief  unpurities  in  clay  from  a  paper-making 
standpoint  are  grit  and  iron.  The  presence  of  an  excess  of  iron 
results  in  a  yellowish  color,  which,  when  not  too  deep,  is  sometimes 


§4  LOADING  5 

corrected  by  the  use  of  a  blue  dye.  English  clays,  for  example, 
are  sometimes  tinted  with  ultramarine,  to  neutralize  the  yellowish 
color.  The  presence  of  grit  is  objectionable  because  of  the  wear- 
ing action  on  the  paper-machine  parts;  it  dulls  the  cutter  knives, 
causes  holes  in  the  finished  paper,  and  creates  excessive  wear  on 
the  printing  plates.  Some  American  clays  are  reddish-yellow 
when  wet,  but  are  white  when  dry;  this  is  not  an  objectionable 
feature  in  paper  making,  since  the  color  when  dry  should  be  the 
controlling  factor. 

It  is  widely  believed  that  for  other  reasons  besides  color, 
English  clays  are  superior  to  those  found  here  in  America;  it  is 
generally  held  that  the  desired  qualities  of  finish,  feel,  opacity, 
and  ink-absorbing  power  cannot  be  obtained  by  using  domestic 
(American)  clay  alone.  That  there  is  a  difi'erence  between 
domestic  and  English  clays  is  shown  by  the  variation  in  the  time 
of  slaking  that  characterizes  the  two  groups.  If  lumps  of 
domestic  and  English  clay  are  put  in  a  pan  of  water,  it  will  be 
noticed  that  the  time  required  for  the  water  to  disintegrate  the 
clay  lumps  is  much  shorter  for  imported  than  for  domestic 
clays.  This  difference  is  sometimes  attributed  to  the  fact  that, 
while  a  wet  process  may  have  been  used  in  purifying  both  classes, 
the  English  clay  is  allowed  to  settle  and  the  water  is  then  drawn 
off;  whereas  in  America,  filter  presses  are  used,  and  the  pressure 
employed  in  these  presses  is  said  to  affect  the  speed  of  slaking. 

6.  Properties  of  Clay. — Chemically,  clay  is  a  hydrated  alumi- 
num silicate,  containing  approximately  40%  AI2O3,  46%  SiOz, 
and  14  %  H2O  (water).  Physically,  it  is  a  yellowish  to  bluish- 
white  substance,  having  a  smooth,  greasy  feel,  and  possessing  the 
characteristic  property  of  making  a  "slip"  or  "slurry"  on  the 
addition  of  water.  This  slurry  is  merely  a  suspension  of  clay  in 
water;  but  it  may,  at  times,  be  almost  a  colloidal  solution.  If  a 
sample  of  good  English  china  clay  be  shaken  or  stirred  with 
about  four  times  its  weight  of  water  for  two  hours  and  then 
allowed  to  stand,  it  will  be  noticed  that  it  settles  very  slowly. 
The  time  of  stirring  that  is  necessary  will  vary  somewhat  with  the 
clay  used.  Talc  or  agalite  when  treated  in  the  same  way  settles 
very  quickly. 

Clay  is  the  most  finely  divided  of  our  common  fillers;  it  has  a 
better  color  than  most  talcs  or  agalites,  but  not  as  good  a  color  as 
pearl  or  crown  filler.  The  discoloration  may  be  due  to  iron  or 
organic  matter. 


LOADING  AND  ENGINE  SIZING 


§4 


7.  Quantity  of  Clay  Used  in  Paper. — The  quantity  of  clay  used 
in  book  paper,  which  is  the  grade  in  which  the  greatest  tonnage  is 
used,  is  generally  from  10%  to  20%  of  the  weight  of  the  paper, 
although  as  much  as  40%  is  sometimes  found  in  papers  that  are 
to  be  given  a  very  high  finish,  in  order  to  take  fine  line-cuts  or 
half-tone  prints;  smaller  amounts,  from  5%  to  10%,  are  used  in 
cheap  writings,  tablets,  etc.  Up  to  5%  is  sometimes  used  in 
newsprint. 

8.  Methods  of  Handling. — Before  clay  is  added  to  the  beater, 
it  is  usually  made  up  with  water  (1  to  2^  pounds  of  clay  per  gallon) 
and  screened  to  remove  dirt.     Sometimes  j%  to  ^  %  of  sodium 


ToBeaters 


Fig.  1. 
Legend:  A,  car;  B,  crusher;  C\  and  C2,  spiral  (worm)  conveyors;  D,  bucket  elevator; 
E,  stairway;  F,  chutes  to  bins  and  tanks;  G,  mixing  tanks;  H,  two  storage  bins,  with  spiral 
conveyor  in  the  center  of  the  bottom  of  each;  K,  4  clay-milk  storage  tanks;  L,  automatic 
weighing  hoppers;  M,  motors;  A^,  alum  and  size  house;  0,  platform;  P,  revolving  screens; 
R,  pump;  T,  pipe  line  to  storage  tanks. 

silicate  (based  on  the  weight  of  clay  used)  is  added  when  mixing 
with  water;  this  is  said  to  reduce  greatly  the  viscosity  of  the 
solution,  thus  making  the  screening  easier.  Other  alkalis,  as 
caustic  soda,  bring  about  a  similar  result.  Care  must  be  exercised 
in  the  use  of  such  substances,  because  of  possible  undesired  effects 
on  other  materials,  as  size  and  coloring. 

9.  There  are  many  waj'^s  of  handling  clay;  sketches  of  two 
arrangements  are  given  herewith.  The  first  of  these,  outlined  in 
Fig.  1,  gives  the  course  of  the  filler  from  railroad  car  to  the  storage 
tanks  for  the  clay-and-water  slip  (slurry).     The  numbers  refer 


§4 


LOADING 


to  the  order  or  sequence  of  operations  and  the  letters  to  the  cut 
(illustration).  1,  clay  is  transferred  from  cars  A  to  a  receiving 
hopper;  2,  to  crusher  ^;  3,  to  elevator  feeder  Ci;  4,  to  bucket 
elevator  D;  5,  to  distributing  conveyor  d;  6,  to  bins  H;  7,  to 
reclaiming  conveyor;  8,  to  scale  hopper  L;  9,  to  bucket  elevator,  as 
in  D;  10,  to  distributing  conveyor;  11,  to  mixing  tanks  G;  12,  to 
revolving  sifter  screens  P;  13,  to  storage  tanks  K. 

10.  A  much  simpler  system  is  shown  in  Fig.  2.  In  this  case, 
the  clay  (received  in  bulk)  in  cars  A  is  shoveled  into  a  chute  B, 
which  deposits  it  on  a  conveyor  C.     By  this  means,  it  is  distrib- 


J 


^. 


G 


E. 


B 


D 


Fig.  2. 

uted  to  any  part  of  the  clay  storage  bin  D.  As  needed,  clay  is 
drawn  from  storage  in  carts,  and  is  mixed  with  water  in  tanks  Ei 
and  Ei.  Each  of  these  tanks  should  hold  at  least  a  1 2-hour 's 
supply.  The  agitators  in  these  tanks  should  run  at  about 
8  r.p.m. ;  they  should  pass  close  enough  to  the  bottom  to  keep  the 
clay  thoroughly  stirred  up.  Water  is  run  in  fast,  and  the  agita- 
tor started;  then  the  clay  is  added,  gradually.  From  the  mixers, 
the  clay-milk  is  pumped  to  storage  tanks  G,  and  from  thence  to 
the  measuring  tanks  I,  there  being  one  of  the  latter  for  every  set 
of  beaters.  By  placing  tank  G  on  a  higher  level,  the  clay  slurry 
can  be  run  by  gravity  to  7,  and  from  the  latter  to  the  beaters. 


TALC 

11.  Occurrence. — The  largest  deposits  of  talc  are  in  Vermont 
and  northern  New  York.  There  are  a  number  of  varieties  of  talc, 
several  sometimes  occurring  together;  they  differ  from  one 
another  in  color,  hardness,  and  crystalline  form,  which  accounts 
for  the  non-uniformity  observed  in  the  appearance  of  talcs  when 
examined  under  the  microscope.  In  some  cases,  each  variety  is 
mined  separately,  but  more  often  as  they  occur,  without  separa- 


LOADING  AND  ENGINE  SIZING 


§4 


Fig.  3. 


Fig.  4. 


§4 


LOADING 


Fig.  5. 


Fig.  6. 


10  LOADING  AND  ENGINE  SIZING  §4 

tion.     In  the  early  days  of  the  industry,  some  surface  mining  was 
done;  but  the  work  is  almost  wholly  underground  now. 

12.  Treatment. — After  the  rock  is  brought  to  the  surface,  it  is 
sorted,  broken  in  a  jaw  crusher,  then  between  rolls,  and  is  then 
finally  ground  in  a  roller  mill,  a  tube  mill,  or  in  an  intermittent- 
operating  pebble  mill.  The  finished  product  is  screened  only,  or 
is  air-separated,  depending  on  the  degree  of  fineness  required. 
Under  the  microscope,  it  is  generally  seen  as  flat  plates  of  many 
sizes.     (See  Fig.  5.) 

13.  Properties. — Chemically,  talc  is  a  hydrated  magnesium 
silicate,  giving  by  analysis  approximately  32%  MgO,  63%  Si02, 
and  5%  H2O  (water).  Physically,  it  is  a  greenish-gray  substance 
having  a  soapy  feel.     Soapstone  is  a  variety  of  talc. 

14.  Uses. — Talc  is  one  of  the  natural  fillers;  it  is  much  used  in 
book  papers,  particularly  those  which  are  not  to  be  used  for  fine 
printing,  as  line  cuts,  half-tones  and  other  delicate  plates.  It  is 
not  suited  to  the  latter,  because  the  comparatively  sharp,  hard 
particles  of  talc  are  large  enough  to  wear  the  printing  plates 
badly,  thus  causing  fine  lines  to  blur.  The  use  of  talc  tends  to 
soften  the  sheet  and  improve  the  printing  qualities,  but  to  a  less 
degree  than  does  clay.  To  a  certain  extent,  a  shiny  appearance 
and  a  slippery  feel  is  given  the  paper.  It  is  generally  used  in 
smaller  quantities  than  clay,  from  3%  to  20%,  averaging  10%. 

The  objections  to  its  use  are  the  possibility  of  the  presence  of 
grit,  "shiners"  (pieces  of  mica),  carbonates,  and  iron.  On  the 
other  hand,  talc  is  cheaper  than  clay,  has  a  higher  retention  (see 
Art.  23),  and  it  can  be  added  to  the  beater  dr}^  as  received; 
whereas  clay  must  be  carefully  mixed  with  water  before  adding. 
Probably  its  most  desirable  use  is  to  soften  the  cheaper  writing, 
tablet,  papeterie,  and  similar  papers,  in  which  it  is  used  in  quanti- 
ties of  from  3%  to  10%.  It  serves  to  remove  that  " woody"  feel 
to  some  extent.  Its  color  is,  in  general,  poorer  and  less  satis- 
factory than  any  of  the  other  fillers. 


OTHER  FILLERS 

15.  Agalite. — In  many  ways,  agalite  is  similar  to  talc;  chemic- 
ally, it  is  identical  with  talc.  Physically,  it  is  less  soapy  than 
talc,  but  has  much  the  same  general  color.  Under  the  micro- 
scope, it  is  supposed  to  appear  as  long  needle-like  crystals.  A 
careful  examination  of  many  commercial  samples  of  talc  and 


§4  LOADING  11 

agalite  has  shown  that  these  substances  grade  into  each  other 
as  regards  crystal  form. 

The  properties  of  agaUte,  drawbacks  to  its  use,  etc.  are  much 
the  same  as  in  the  case  of  talc,  but  the  former  is  considered  to  be 
more  wearing  on  paper-machine  clothing  parts  and  on  printing 
plates ;  it  tends  to  wear  the  fine  lines  on  the  latter  and  to  fill  them 
with  dust.  For  this  reason,  it  is  not  used  to  the  same  extent  as 
clay  or  talc,  especially  in  book  papers.  Agalite  should  not  be 
used  in  quantity  in  papers  that  are  to  be  cut  or  punched,  because 
it  dulls  the  steel  cutting  edges.  Its  color  is,  in  general,  a  gray, 
somewhat  lighter  than  talc,  and  lacks  the  characteristic  green 
tint  of  the  latter. 

16.  Asbestine. — Asbestine  is  a  filler  that  much  resembles  talc 
and  agalite;  under  the  microscope,  it  appears  as  a  mixture  of 
these  two.  Its  use  and  properties  are  a  sort  of  a  compromise,  as 
would  be  expected  from  this  crystal  formation.     (See  Fig.  6.) 

17.  Crown  Filler. — Crown  filler  has  by  far  the  purest  white 
color  of  any  of  the  fillers;  it  is  also  known  as  pearl  hardening. 
Crown  filler  is  an  artificial  (manufactured)  product,  as  distin- 
guished from  clay,  talc,  agalite,  and  pearl  filler,  which  are  mined. 
It  is  made  as  a  precipitate  by  the  interaction  of  solutions  of 
CaCl2  and  NaHS04.  Chemically,  it  is  calcium  sulphate,  with 
two  molecules  of  water  of  crystalhzation  CaS04-2H20.  The 
dry  substance  shows,  on  analysis,  79%  CaS04  and  21%  H2O. 
By  water  of  crystallization  is  meant  water  chemically  combined, 
so  that  a  substance  containing  it  can  appear  to  be  quite  dry  while 
containing,  in  some  cases,  as  much  as  50%  water.  Crown  filler 
appears  on  the  market  as  a  wet  powder  that  contains  33  %  water, 
of  which  21%  is  chemically  combined  and  the  remainder  is 
mechanically  mixed.     (See  Fig.  4.) 

Owing  to  the  methods  of  manufacture,  crown  filler  can  be  kept 
free  from  grit  and  very  low  in  iron  and  in  acid  content.  Exten- 
sive mill  and  laboratory  tests  have  shown  that  free  acid,  figured 
as  hydrochloric  acid,  should  not  be  over  0.05%,  based  on  the 
sample  as  received;  more  than  this  may  cause  trouble  with  the 
rosin  sizing.  It  is  the  most  soluble  of  the  fillers,  about  30  pounds 
being  dissolved  in  1000  gallons  of  pure  water  at  ordinary  room 
temperature.  At  this  rate,  from  60  to  80  pounds  are  dissolved 
in  the  water  contained  in  an  ordinary  1000-pound  beater;  there- 
fore, if  less  than  10  pounds  of  crown  filler  per  100  pounds  of  fiber 


1-2  LOADING  AND  ENGINE  SIZING  §4 

are  added  to  the  beater,  almost  no  calcium  sulphate  is  found  in 
the  furnished  paper.  The  solubility  is  less  when  hard  water  is 
used,  and  it  is  decreased  by  the  addition  of  alum.  The  quantities 
of  crown  filler  used  are  generally  40%  to  50%  of  the  fiber  furnish. 

This  filler  is  particularly  useful  in  high-grade  papeteries,  where 
a  high  white  color  or  delicate  tints  are  desired.  As  it  is  the  most 
expensive  of  the  fillers  and  has  the  lowest  retention,  its  use  is 
necessarily  confined  to  the  better  grades  of  paper.  When  present, 
it  interferes  somewhat  with  the  rosin  sizing  of  the  sheet,  because, 
owing  to  its  solubility,  enough  calcium  sulphate  is  in  the  solution 
to  react  with  the  rosin  size,  precipitating  a  calcium  resinate,  or 
calcium  soap,  which  has  no  sizing  value.  A  similar  effect  on 
sizing  is  observed  when  very  hard  water  is  used. 

18.  Pearl  Filler. — Chemically,  pearl  filler  is  the  same  as  crown 
filler,  except  that  there  is  no  water  of  crystaUization  and  only 
about  1  %  of  mechanical  water.  It  is  found  in  nature,  as  are  talc 
and  agalite,  and  has  merely  to  be  ground  and  sifted  to  prepare  it 
for  use.  The  alkalinity  is  about  the  same  as  talc,  1%  to  2%, 
figured  as  CaCOs,  and  the  grit  is  less.  In  color,  it  is  not  equal  to 
crown  filler,  but  it  is  far  better  than  in  any  of  the  other  fillers.  It 
is  less  expensive  than  crown  filler  and  its  retention  is  greater.  The 
chief  reason  for  its  greater  retention  is  that  of  each  100  pounds  of 
crown  filler  added  to  the  beater,  33  pounds  is  water,  while  pearl  filler 
is  almost  free  from  water.  Pearl  filler  is  used  chiefly  in  medium- 
grade  papeteries  and  writings,  and  it  is  added  to  the  beater  dry. 


FILLERS  FOR  SPECIAL  PAPERS 

19.  Chalk. — In  addition  to  those  already  described,  a  number 
of  other  fillers  are  used  for  very  special  papers.  Chalk  (the 
ground  mineral),  or  calcium  carbonate  (precipitated  for  this 
purpose),  is  used  in  amounts  as  high  as  30%  in  cigarette  paper. 
Its  use  speeds  up  the  burning  of  the  paper,  because,  when  the 
paper  is  heated,  carbon  dioxide  gas  is  given  off;  this  opens  the 
pores  of  the  paper  and  promotes  combustion.  Chalk  also 
improves  the  color  of  the  ash. 

20.  Barytas. — Barytes,  or  barium  sulphate,  is  used  in  photo- 
graphic papers  on  account  of  the  special  surface  imparted  to  the 
sheet;  it  is  quite  expensive,  and  its  retention  is  low  because  of 
its  weight.  It  is  also  used  in  some  special  printing  papers  that 
must  be  very  flat,  it  being  held  that  the  weight  of  the  filler  holds 


§4  LOADING  13 

the  paper  down.     This  filler  is  usually  prepared  by  adding  a 
soluble  sulphate  to  a  solution  of  barium  chloride. 

21.  Oxide  of  Iron  and  Wilkinite. — Oxide  of  iron  is  sometimes 
used  to  color  leather  board  and  box  board,  and  to  act  as  a  filler 
at  the  same  time.  This  material  is  said  to  give  trouble,  however, 
due  to  the  pitting  of  press  and  calender  rolls;  this  effect,  is  especially 
to  be  noted  on  the  latter,  if  a  water  finish  is  being  applied. 

Recently,  work  has  been  done  on  a  very  highly  colloidal,  clayey 
substance  that  is  known  to  the  trade  as  wilkinite,  geologically 
called  bentonite.  This  material  appears  to  have  the  property 
of  retarding  the  settling  of  clay  suspensions.  The  indications 
are  that  it  will  also  increase  the  retention  of  filler  in  paper. 

22.  The  Microscopic  Appearance  of  Fillers. — In  Figs.  3,  4,  5, 
and  6,  are  shown  photomicrographs  of  four  commonly  used  fillers. 
These  were  prepared  by  the  Paper  Section,  Bureau  of  Standards 
(United  States).  They  show  the  marked  difference  between  the 
finely  divided,  colloidal  clay  and  the  highly  crystalline  crown 
filler;  also,  the  similarity  between  talc  and  asbestine.  A  few  of 
the  needle-shaped  crystals  are  visible,  especially  in  the  asbestine. 
The  magnification  in  each  case  was  100  diameters. 


RETENTION  OF  FILLERS 

23.  Per  Cent  of  Retention. — By  retention  of  filler  is  meant  the 
pounds  of  filler  found  in  the  paper  for  each  100  pounds  of  filler 
added  to  the  beater.  To  find  the  per  cent  retention,  divide  the 
weight  of  the  filler  in  the  paper  by  the  weight  of  filler  added  to 
beater  and  multiply  by  100;  thus, 

per  cent  retention  =  — ^^t— — ^/,,r^ — r—^—  X  100 
weight  of  nller  m  beater 

Instead  of  using  the  weights  of  filler,  the  percentage  of  filler  by 
weight  may  be  used,  in  which  case,  care  must  be  taken  in  calcu- 
lating retention  that  the  per  cent  filler  in  the  beater  and  that  in 
the  finished  paper  are  figured  on  the  same  basis,  which  should  be 
the  weight  of  bone-drj''  fiber.  Proper  corrections  should  be  made 
for  the  moisture  content  of  the  original  filler  and  of  the  filler  as  it 
occurs  in  the  paper,  for  the  ash  content  of  the  fiber  furnish,  etc. 
Some  fillers  contain  water  of  constitution  (part  of  the  molecule), 
besides  moisture  held  mechanically;  all  this  water  is  lost  in 
determining  the  ash  content.  The  particular  formula  to  be  used 
in  any  given  case  should  be  picked  out  after  considering  the 


14  LOADING  AND  ENGINE  SIZING  §4 

accuracy  of  the  final  result  that  is  desired.  This  matter  is 
treated  at  length  in  the  Section  on  Paper  Testing,  Vol.V.  The  per 
cent  retention  of  the  filler,  as  determined  by  the  amount  and 
character  of  the  ash,  is  used  in  calculating  the  amount  of  filler 
that  must  be  added  to  the  stock.  Allowance  must  be  made  for 
the  solubility  of  the  filler  in  some  cases. 

When  waste  paper  from  the  mill  is  used,  especially  "broke" 
(spoiled  paper),  consideration  must  be  giv^en  to  any  filler  that  may 
be  contained  in  it.  It  will  be  seen,  too,  that  any  filler  contained 
in  white  water  that  may  be  used  in  the  beater  or  on  the  machine, 
will  affect  the  retention  of  the  filler  added ;  this  water  may  become 
saturated,  so  to  speak,  with  filler. 

24.  Conditions  Afif acting  Retention. — The  retention  of  any 
given  filler  will  vary  widely,  according  to  stock  and  machine  con- 
ditions. Other  things  being  equal,  retention  increases  as  the 
weight  of  the  sheet,  the  slowness  (hydration)  of  the  stock,  or  as 
the  length  of  the  fiber  increases.  It  decreases  as  the  speed  of  the 
machine  increases,  and  as  the  amount  of  suction  on  boxes  and  rolls 
increases.  Retention  is  greater  in  a  well-sized  sheet  than  in  a 
slack-sized  sheet;  with  mechanical  and  sulphite  pulps,  it  seems  to 
decrease  with  the  length  of  fiber.  Other  conditions  being  the  same, 
but  using  different  fillers,  the  retention  increases  as  the  size  of  the 
filler  particles  increases,  and  as  the  specific  gravity  or  weight 
per  cubic  foot  decreases.  Retention  decreases  as  the  solubility 
and  moisture  content  of  the  filler  increases.  Other  conditions 
affecting  retention  are  the  amount  of  shake  of  the  machine, 
and  the  quantity  of  fresh  water  or  of  white  water  used.  The  reten- 
tion is  less  than  the  normal  by  from  10%  to  20%,  if  the  amount  of 
filler  added  is  less  than  about  5%  or  greater  than  30%  of  the 
weight  of  the  fiber;  this  last  does  not  apply  to  crown  filler,  which 
reaches  its  maximum  retention  with  additions  of  50%  to  60%,  nor 
to  pearl  filler. 

Unfortunately,  little  retention  data  for  pearl  filler  are  available. 
It  seems,  however,  that  the  ratio  of  bone-dry  calcium  sulphate, 
with  no  water  of  crystallization  retained,  to  bone-drj'-  calcium 
sulphate  added,  is  approximately  the  same  for  both  crown  and 
pearl  fillers,  when  large  amounts  are  used.  Crown  filler  usually 
contains  about  33  %  of  water  whereas  pearl  filler  contains  almost 
none  at  all.  If  the  retention  is  based  on  the  actual  pounds  of  filler 
added,  irrespective  of  moisture  content,  the  retention  of  pearl 
filler  would  be  about  half  again  as  great  as  that  of  crown  filler. 


LOADING 


15 


25.  Some  Retention  Data. — The  following  data  are  based  on 
papers  having  a  folio  weight  (standard  substance  number  or 
weight  per  ream  of  500  sheets,  17  inches  X  22  inches)  of  about  20 
pounds,  an  addition  of  filler  of  10%  to  20%,  and  a  machine  speed 
of  100  to  200  ft.  per  min.  The  figures  are  average  results;  the 
papers  were  writings  and  envelopes,  with  a  few  book  papers.  The 
retention  to  be  expected  in  book  paper  of  medium  weight  is  about 

Cos+in  Cents  per  Lb.  of  Filler  in  Paper 
55?     ^-^Q    '°Q    '-^Q    ^°°   ^-50     3.00   3.50    4.00    4.50    5.00     5.50   £.00 


25      30       35      40 
Per  Cenf  Reiained 

Fig.  7. 


10%  lower  than  the  figures  obtained,  which  were:  talc,  82%; 
agalite,  75%;  clay,  70%. 

For  crown  filler,  the  following  figures  for  the  same  sheet  weight 
and  range  of  machine  speed  are  given.  The  papers  were  writings 
and  papeteries.^ 


Per  Cent  Added 
(Pounds  Per  100  Pounds  of  Pulp) 

10 
20 
30 
40 
50 
60 


Per  Cent  Retained 
(Based  on  Filler  Added) 

0.0 
13.5 
39.5 
49.0 
52.0 
53.0 


1  Papers  for  fancy  correspondence  bo.xes,  and  the  like. 


16  LOADING  AND  ENGINE  SIZING  §4 

26.  In  Fig.  7,  a  curve  is  given  of  the  retention  of  crown  filler, 
showing  how  this  varies  with  the  amount  added.  Another 
curve  is  also  given,  which  shows  the  variation  in  the  cost  per  pound 
of  filler  in  the  paper  with  the  amount  added  to  the  beater;  the 
rapid  increase  in  cost  when  small  amounts  are  added  is  very 
evident,  and  is  due  to  the  large  percentage  lost.  The  cost  of  this 
filler  dehvered  to  the  mill  was  $1.08  per  100  pounds  when  this 
cost  curve  was  drawn. 

27.  Other  conditions  than  those  mentioned  being  constant, 
retention  of  filler  will  vary  as  follows: 

Retention  Increases  Retention  Decreases 

As  weight  of  sheet  increases;  As  solubility  of  filler  increases; 

As  machine  speed  decreases;  As     amount     added     to     beater 

As  engine  sizing  changes  from  slack  decreases  below  5%; 

to  good;  As     amount     added     to     beater 

As  slowness  of  stock  increases;  increases    above    30%    (except 

As  length  of  fiber  increases;  crown  filler). 
As  size  of  filler  particles  increases; 
As  specific  gravity  of  filler  decreases. 

28.  When  to  Add  the  Filler. — The  proper  time  for  adding  filler 
is  generally  thought  to  be  as  soon  after  "furnishing"  as  possible, 
and  before  the  addition  of  size  and  alum,  as  the  precipitation  of 
size  tends  to  fix  the  filler  in  the  fiber.  The  usual  practice  is  to 
add:  first,  filler;  then,  rosin;  and,  last,  alum. 

Retention  will  be  increased  by  the  use  of  starch  or  sodium 
silicate;  but  it  is  doubtful  whether  the  increase  warrants  the  use 
of  these  materials  for  this  cause  alone.  Some  even  advocate 
boiling  filler  and  starch  together.  It  has  also  been  recommended 
to  mix  the  clay  with  separately  boiled  starch,  and  then  add 
rosin  size  to  the  mixture;  after  which  the  whole  is  added  to  the 
beater.  Unfortunately,  there  is  little  actual  data  available. 
Clay,  however,  should  be  added,  and  it  should  be  thoroughly 
mixed  with  the  stock,  before  alum  is  added;  otherwise,  the  acid 
of  the  alum  will  destroy  the  colloidal  properties  of  the  clay, 
thereby  lowering  retention,  giving  poorer  finish,  etc. 


QUESTIONS 

(1)  What  substances  may  paper  contain,  other  than  fiber? 

(2)  IIow  is  clay  produced?    How  does  it  differ  from  talc? 

(3)  What  chemical  difference  is  noted  between  crown  filler  and  pearl  filler? 

(4)  How  is  clay  usually  added  to  the  beater?     (h)  talc? 

(5)  Would  you  expect  any  difference  in  the  retention  of  crown  filler  in  soft 
water  and  hard  water?    Explain  your  answer. 


§4  LOADING  17 

ANALYSIS  OF  FILLERS 

29.  Sampling. — The  sampling  is  done  by  opening  5%  to  10%, 
preferably  10%,  of  the  barrels  or  packages,  as  received  from  the 
car,  and  taking  a  small  portion  of  each,  making  the  weight  of 
the  total  sample  about  5  pounds.  In  case  of  a  shipment  in  bulk, 
it  is  best  to  take  the  sample  at  frequent  and  regular  intervals, 
as  the  shipment  is  being  unloaded.  From  a  car  of  clay,  the  filler 
most  commonly  shipped  in  bulk,  the  sample  thus  taken  should 
weigh  about  50  pounds,  and  should  represent  both  the  fine  and 
coarse  portions.  The  lumps  should  be  broken  up  and  the  sample 
quartered  down,  until  it  will  about  fill  a  Mason  jar;  this  is  kept 
in  an  air-tight  container  until  the  analysis  is  to  be  performed. 

30.  Preparation  for  Analysis. — The  5-pound  sample  is  care- 
fully mixed,  all  large  lumps  are  broken  up,  and  the  whole  is 
quartered  down  to  about  50  grams.  The  analyst  will  do  well  at 
this  point  to  determine  whether  the  filler  is  clay,  talc,  agalite, 
calcium  sulphate,  etc.  A  qualitative  test  may  also  be  made  for 
acidity. 

31.  Moisture  Content. — Mechanically  combined  moisture  is 
determined  on  2  grams  of  this  sample  by  drying  at  105°C.  to  a  con- 
stant weight.  The  chemically  combined  moisture  may  be 
determined  b}'  placing  this  dried  sample  in  a  crucible  and  heating 
at  the  full  heat  of  a  Meker  burner  until  a  constant  weight  is 
secured;  or  by  heating  2  grams  of  the  original  sample  in  the  same 
manner,  and  then  subtracting  the  mechanical  (surface)  moisture 
from  the  result.  In  the  case  of  crown  filler,  the  total  moisture  is 
determined  by  igniting  a  2-gram  sample  over  a  Meker  burner  to 
constant  weight;  from  this  result,  the  chemically  combined 
moisture  may  be  calculated,  the  molecular  formula  for  crown  filler 
being  CaS04-2H20.  Subtracting  this  result  from  the  original  2 
gi-ams  taken  for  analysis,  the  mechanical  moisture  is  obtained. 

32.  Color. — Color  is  determined  by  comparison  with  a  standard 
sample  that  has  been  selected  for  color.  Small  amounts  of  the 
sample  to  be  compared  and  of  the  standard  are  pressed  together 
on  a  black  paper,  with  a  poHshed  steel  spatula.  Any  difference 
in  color  can  then  be  readily  seen,  and  the  sample  is  reported  to  be 
as  good  as  standard,  yellower,  graj^er,  or  whatever  difference 
is  observed. 

33.  Fineness. — Fineness  ma^^  be  determined  microscopically, 
by  elutriation  or  by  the  sieve  method;  but  neither  method  is 


18 


LOADING  AND  ENGINE  SIZING 


§4 


applicable  to  calcium  sulphate  or  other  appreciably  soluble  fillers, 
because  of  their  solubility.  Fineness  is  determined  most  simply 
microscopically.  A  very  small  amo\mt  of  filler  is  placed  on  a 
glass  slide,  with  a  small  amount  of  water,  and  a  cover  glass  is 
placed  over  the  mixture.  It  is  examined  under  low  power  of  the 
microscope,  comparing  the  sample  with  the  standard,  which  has 
been  treated  in  the  same  way.  If  a  microscope  is  not  available, 
200  grams  of  clay  are  mixed  thoroughly  with  1000  c.c.  of  water  and 
strained  through  a  200-mesh,  silk,  bolting  cloth,  by  use  of  a 
gentle  stream  of  water.  The  material  remaining  on  the  screen 
is  dried  and  weighed.  This  will  give  a  fair  estimate  of  the  per 
cent  of  grit  present. 

34.  Elutriation  Tests. — The  elutriation  test  on  a  filler  gives 
the  per  cent  of  grit  or  coarseness,  but  the  method  is  very  com- 


i  Oyer  f /on 


Overflow 


No.5 


Fig.  8. 


plicated;  for  general  purposes,  microscopic  analysis  is  sufficient. 
Binus'  apparatus  is  very  satisfactory  for  a  careful  elutriation 
test,  and  should  be  used  when  very  careful  analysis  is  necessary. 
The  arrangement  of  this  apparatus  is  shown  in  Fig.  S.  In  making 
the  test,  50  grams  or  100  grams  of  bone-dry  clay  are  weighed  out, 
thoroughly  slaked  (preferably  in  some  sort  of  tumbling  device  in 
which  dupHcate  results  can  be  obtained),  and  strained  through  a 
100-mesh  sieve  into  No.   1  receptacle.     Water  is  then  run  in 


§4  LOADING  19 

at  the  rate  of  2.8  c.c.  per  second,  giving  a  rate  of  flow  of  1.5, 
0.7,  0.18,  0.08,  and  0.04  mm.  per  sec.  in  the  various  receptacles, 
which  progressively  increase  in  size,  the  smallest  having,  of 
course,  the  highest  rate  of  flow.  The  flow  should  be  continued 
until  the  water  from  the  last  receptacle  is  clear;  then  weigh  the 
various  residues.  There  will  probably  be  little  or  none  in  the  first 
two,  and  it  will  probably  be  found  that  the  residue  in  the  third 
receptacle  is  the  best  measure  of  the  fineness  of  the  sample. 
There  are  several  other  types  of  elutriating  apparatus  on  the 
market,  as  those  of  Schone  or  Hilgard.  This  subject  is  very 
fully  covered  in  Wiley's  "Principles  and  Practice  of  Agricultural 
Analysis."     The  Schone  apparatus  gives  very  accurate  results. 

35.  The  following  method  will  give  tests  for  comparing  two 
fillers.  A  10-gram  sample  of  the  filler  is  placed  in  a  glass  cjdinder, 
llf  inches  high  and  If  inches  in  diameter,  and  which  holds  400  c.c. 
The  filler  is  thoroughly  shaken  up  with  a  small  amount  of  water, 
and  the  cylinder  is  filled  to  the  top.  From  a  large  bottle,  58  inches 
above  the  bottom  of  this  glass  cyhnder,  2500  c.c.  is  allowed  to 
pass  through  the  cylinder  from  a  glass  tube,  |  inch  in  diameter, 
extending  to  the  bottom  of  the  cylinder.  The  residue  is  then 
filtered  on  a  tared  filter,  dried,  and  weighed ;  this  gives  the  amount 
of  grit  or  coarseness  in  the  filler.  Variation  in  the  rate  of  flow  of 
the  water  can  be  made  to  suit  special  conditions.  Other  things 
being  equal,  the  greater  the  rate  of  flow  the  larger  the  particles 
carried  out  of  the  cylinder,  and  the  smaller  the  apparent  amount 
of  grit  in  the  sample.  The  amount  of  grit  in  any  filler  should  be 
less  than  1.5%.  When  a  partially  soluble  filler  is  tested,  the 
water  used  must  be  saturated  with  it,  and  the  temperature  must 
be  kept  constant. 

36.  Sieve  Test. — For  the  sieve  test,  which  is  not  so  reliable  as 
the  elutriation  test,  a  set  of  standard  sieves,  from  No.  100  to 
No.  325,  inclusive,  is  recommended.  These  numbers  have  been 
given  to  a  scientifically  determined  series  and  correspond  approx- 
imately to  the  ordinary  mesh.  These  should  be  small,  and  be 
light  enough  to  permit  the  residue  to  be  weighed  on  the  sieve  with- 
out transferring  to  tared  filter  paper.     This  method  is  as  follows : 

Place  the  weighed  sample  of  clay  in  a  beaker  and  add  distilled 
water.  For  a  50-gram  sample,  add  500  c.c.  of  water.  Let  stand 
for  one-half  hour,  and  then  agitate  thoroughly,  but  without 
grinding.     Let  stand  for  a  few  minutes,  for  the  coarse  material 


20  LOADING  AND  ENGINE  SIZING  §4 

to  settle  in  the  bottom,  and  decant  through  the  weighed  sieve, 
which  has  been  previously  cleaned  and  dried  in  an  oven  at  105°  to 
110°C.  Decant  a  small  portion  slowly  through  the  screen,  and 
wash  out  with  water.  Gradually  transfer  the  suspended 
material,  finally  leaving  the  coarse  particles  on  the  sieve.  With 
proper  manipulation,  a  large  portion  of  the  sample  will  pass 
through  the  sieve  during  the  process  of  transference.  If  the 
contents  are  dumped  on  the  sieve  at  one  time,  the  coarse 
particles  will  clog  the  holes,  which  will  cause  the  sieving  operation 
to  prove  difficult,  often  impossible,  unless  the  sediment  is  stirred 
with  the  hand.  Such  hand  stirring  or  rubbing  of  the  material 
through  the  sieve  is  strongly  to  be  condemned ;  it  not  only  forces 
through  the  larger  particles  but  it  also  permanently  distorts  the 
apparatus,  so  that  the  sieve  is  rendered  worthless.  Gently  tap 
the  sieve  while  washing  under  a  stream  of  water.  Toward  the 
end,  it  will  be  found  more  efficient  to  place  some  water  in  a  dish 
and  to  set  the  sieve  in  this;  then,  by  a  shaking  motion,  the  sieve 
is  washed  from  below.  Such  washing  will  remove  the  fine  parti- 
cles much  more  quickly  than  by  placing  water  on  the  sieve  with 
the  residue.  By  having  a  dish  painted  black,  the  thoroughness 
of  washing  a  white  pigment  will  be  apparent.  Finally,  heat  the 
sieve  for  1  hour  at  105°  to  110°C.,  cool,  and  weigh. 

When  properly  used  and  cared  for,  sieves  should  be  reliable 
for  a  number  of  years.  No  washers,  shot,  or  other  device  for 
hastening  the  sieving  process  should  ever  be  used.  The  follow- 
ing table  gives  the  sizes  of  the  wires  and  openings  for  standard 
sieves  from  No.  100  to  No.  325. 


Sieve  No. 

100 

Opemivq  in 
Ini'hes 

0.0059 

Wire  Diameter, 
Inches 

0.0040 

120 

0.0049 

0.0034 

140 

0.0041 

0.0029 

170 

0.0035 

0.0025 

200 

0.0029 

0.0021 

230 

0.0025 

0.0018 

270 

0.0021 

0.0016 

325 

0.0017 

0.0014 

37.  Alkalinity. — Alkaline  fillers  are  likely  to  have  an  injurious 
effect  on  sizing  and  coloring,  and  where  they  must  be  used, 
proper  precautions,  such  as  in  selecting  colors,  should  be  taken. 

The  alkalinity  due  to  carbonates  and  bicarbonates  may  be 
determined  by  any  of  the  standard  methods  for  the  determination 


§4  LOADING  21 

of  carbon  dioxide  CO2;  that  is,  by  treating  with  acid  and  weigh- 
ing the  CO2  absorbed  in  KOH  or  soda  lime.  The  advantage 
of  the  following  method  is  that  it  does  not  involve  the  purchas- 
ing of  elaborate  apparatus,  and  it  is  more  accurate  and  quick 
for  routine  work  to  determine  small  amounts  volumetrically  and 
gravimetrically.^ 

The  apparatus  consists  of  two  1000-c.c.  gas-washing  bottles, 
filled  with  20%  solution  of  NaOH  for  the  purpose  of  removing 
CO2  from  the  air.  These  flasks  are  connected  to  a  250-c.c. 
Erlenmeyer  flask  that  is  fitted  with  a  rubber  stopper,  through 
which  a  dropping  funnel  is  passed.  The  outlet  of  the  Erlen- 
meyer flask  is  connected  with  a  train,  which  consists  of  four 
50-c.c.  Nessler  tubes,  fitted  up  as  washing  bottles.  The  tube 
nearest  the  Erlenmeyer  flask  remains  empty,  and  serves  as  a 
trap  for  any  vapors  or  solid  particles  that  may  be  carried  over 
mechanically  from  the  generating  flask.  The  next  three  tubes 
contain  exactly  25  c.c.  of  N/2  NaOH  solution.  The  last  tube 
is  connected  to  the  suction,  and  a  constant  current  of  air,  free 
from  CO2,  is  drawn  through  the  apparatus.  In  making  the 
determination,  10  grams  of  filler  is  weighed  into  a  mortar  and  tritu- 
rated with  two  15-c.c.  portions  of  water.  The  residue  is  then 
washed  into  the  Erlenmeyer  flask,  the  total  volume  of  solution 
being  about  50  c.c.  The  apparatus  is  connected  up.  The 
pinch  cocks  are  opened  on  the  connection  between  the  Erlen- 
meyer flask  and  the  wash  bottles  on  the  one  side,  and  the  first 
and  second  Nessler  tubes  on  the  other  side.  A  current  of  air, 
free  from  CO2,  is  drawn  through  the  apparatus  at  a  moderate 
rate.  During  this  time,  the  Erlenmeyer  flask  is  shaken  occa- 
sionally. In  a  dropping  funnel  50  c.c.  of  a  10%  alum  solution 
is  placed,  the  stop  cock  is  opened,  and  the  alum  is  allowed  to  run 
into  the  Erlenmeyer  flask,  care  being  taken  that  the  alum  does 
not  run  into  the  flask  fast  enough  to  force  the  filler  emulsion 
backward  into  the  wash  bottles.  A  column  of  alum  solution 
should  be  allowed  to  remain  in  the  stem  of  the  funnel  as  a  seal. 
An  hour  after  the  alum  solution  is  all  added,  the  pinch  cocks  are 
closed  and  the  suction  shut  off.  The  contents  of  the  last  three 
Nessler  tubes  are  washed  carefully  into  a  flask,  and  are  titrated 
with  standard  N/2  acid,  using  phenolphthalein  as  an  indicator, 
until  an  end  point  is  reached;  then  methyl  orange  is  added, 

'Quantitative  Analysis;  Treadwell  and  Halls  Quantitative  Analysis  and 
Mahin's  Quantitative  Analj'sis  are  suggested  as  reference  works  on  labora- 
tory procedure  and  general  analysis. 


22  LOADING  AND  ENGINE  SIZING  §4 

and  the  titration  is  completed.  A  blank  consisting  of  25  c.c. 
of  N/2  NaOH  solution  is  titrated  with  N/2  acid  in  the  same 
manner.  Phenolphthalein  titrates  one-half  the  carbonates 
present  and  all  of  the  hydrates  present,  and  methyl  orange 
titrates  the  other  half  of  the  carbonates.  Calculate  the  alkalin- 
ity in  terms  of  calcium  carbonate,  by  multiplying  the  methyl 
orange  titration  by  2  and  then  by  0.02504. 

The  alkalinity  due  to  calcium  carbonate  is  of  chief  importance 
in  a  paper  filler,  and  should  be  kept  under  5%.  Excess  alkahn- 
ity  tends  to  kill  rosin  size,  causes  excess  foam,  and  maj'-  alter  the 
shade  of  certain  dye  stuffs. 

38.  Iron. — Take  2  grams  of  sample  and  dissolve  in  10  c.c.  CP* 
Cone.  HCl.  If  there  is  any  residue,  fuse  it  with  sodium  carbon- 
ate, dissolve  in  concentrated  hydrochloric  acid,  and  add  to  the 
main  portion  of  the  solution.  Wash  dissolved  filler  into  alOO-c.c- 
Nessler  tube,  and  add  a  few  drops  of  a  N/10  KMnO*  solution, 
to  be  sure  that  the  iron  is  oxidized  to  a  ferric  condition.  The 
color  of  the  potassium  permanganate  KMn04  should  persist 
for  at  least  two  minutes.  Add  10c. c.  of  potassium  sulpho- 
cyanide  KCNS  solution  (2%  solution),  and  make  up  to  100  c.c, 
mixing  thoroughly.  Compare  immediately  the  resulting  color 
with  a  standard  that  has  been  prepared  at  the  same  time,  by 
adding  a  standard  iron  solution  (1  c.c.  =  0.00001  gram  FeaOs) 
to  another  Nessler  tube,  which  contains  two  or  three  drops  of 
KMn04  solution,  10  c.c.  of  KCNS  solution,  and  85  c.c.  of  H2O, 
until  the  same  color  is  produced  in  both  tubes.  The  number  of 
cubic  centimeter  of  iron  solution  used  multiplied  by  5  gives  the 
parts  of  Fe203  per  milHon.  Iron  solution  is  best  prepared  by  dis- 
solving 1  gram  of  pure  ironwireinasmallamountofH2S04,  oxidiz- 
ing this  with  N/10  KMn04,  and  making  up  to  1000  c.c.  By  diluting 
a  httle  of  this  solution  100  times,  a  solution  containing  0.00001  gram 
Fe203  is  obtained.  The  amount  of  iron  in  fillers  used  in  paper- 
making  should  be  kept  very  low,  especially  in  a  filler  partially 
soluble  in  water,  as  crown  filler,  where  the  iron  content  should 
not  exceed  0.005%.  In  fillers  that  are  insoluble  in  water,  the 
presence  of  iron  is  usually  detected  by  the  high  yellow  color 
that  makes  them  unsatisfactory  for  paper  making. 


QUESTIONS 

(1)  How  should  a  sample  of  filler  be  taken  and  prepared  for  analysis? 

(2)  Explain  the  testing  of  a  filler  for  alkalinity.     Why  is  this  important? 


LOADING  AND  ENGINE 
SIZING 

(PART  2) 
By  Judson  a.  DeCew,  B.  A.  Sc. 


ENGINE  SIZING 


HISTORICAL 

39.  Tub  Sizing. — In  the  early  days  of  its  manufacture,  when 
it  was  made  by  hand  in  small  sheets,  the  method  of  rendering 
paper  non-absorbent  consisted  entirely  of  surface  sizing,  which 
was  effected  by  dipping  the  finished  sheets  into  a  solution  of  glue 
or  gelatine  (prepared  from  hides),  after  which  the  paper  was 
air-dried.  This  process  is  known  as  tub  sizing,  and  the  size 
used  is  called  animal  size.  Further  details  of  this  practice  and 
the  method  of  its  application  under  modern  conditions  are 
given  in  the  Section  on  Tub  Sizing  ond  Finishing  Operations, 
Vol.  V.  This  practice  continued  until  1807,  when  rosin  sizing 
was  discovered  by  Maritz  Illig  of  Erbach,  Frankfort,  Germany. 

40.  Rosin  Sizing. — Briefly  stated,  the  process  of  rosin  sizing 
consists  in  adding  to  the  stock  in  the  beater  a  sufficient  quantity 
of  a  soap  made  by  cooking  rosin  (which  is  a  mixture  of  organic 
anhydrides)  with  a  solution  of  caustic  soda  or  soda  ash.  When 
this  soap,  which  may  or  may  not  contain  rosin  in  excess  of  the 
amount  necessary  to  combine  with  the  soda,  is  thoroughly  mixed 
with  the  stock,  alum  (aluminum  sulphate)  is  added,  either  in 
powdered  form  or  in  solution.  The  alum  causes  the  rosin  to  be 
precipitated  on  the  fibers  in  the  stock,  together  with  a  certain 
amount  of  aluminum  hydrate.  When  first  formed,  this  precip- 
itate is  gelatinous;  and,  when  mixed  with  the  paper  stock,  is 
spread  over  the  individual  fibers.  When  the  stock  is  run  on  the 
§4  23 


24  LOADING  AND  ENGINE  SIZING  §4 

machine  and  dried,  this  h3^drated  or  resinous  material  hardens, 
and  forms  a  coating  that  is  more  or  less  water  repellent,  which 
completes  the  sizing  operation.  The  degree  to  which  the  paper 
is  made  impervious  to  water  depends  on  the  amount  of  rosin  and 
alum  used,  the  phj-sical  properties  of  these  substances  when  the 
precipitate  was  first  formed  in  the  beater,  the  kind  and  quantities 
of  fiber  and  loading,  the  manner  of  beating,  temperature  of 
machine  dryers,  etc. 


MATERIALS  USED  IN  SIZING 


ROSIN  AND  SODA  ASH 

41.  Sources  of  Rosin. — Rosin  is  the  trade  (or  common)  name 
of  the  substance  otherwise  known  as  colophony,  which  is  the 
residue  left  in  the  still  after  the  distillation  of  the  turpentine  and 
pine  pitch.  Pitch,  or  oleo  resin  is  obtained  from  a  large  number 
of  species  of  pine;  but  the  chief  commercial  source  is  the  longleaf 
and  shortleaf  pine  of  the  Southern  States.  These  trees  are  tapped 
by  cutting  the  bark  and  allowing  the  resin  to  exude  and  flow 
into  cups  in  the  form  of  a  thick  liquid,  which  is  collected  and 
distilled.  During  distillation,  the  turpentine  distills  over  and  is 
collected  separately;  the  residue  in  the  still  is  roughly  filtered, 
while  molten,  and  forms  the  rosin  of  commerce. 

42.  Grades  of  Rosin. — Rosin  is  graded  into  a  large  number  of 
classes,  according  to  the  depth  of  color  and  the  amount  of  impuri- 
ties it  contains.  The  grades  are  designated  by  the  letters  of  the 
alphabet,  those  bearing  the  first  letters  of  the  alphabet  being  the 
lowest  in  quality  and  the  darkest  in  color.  The  highest  grades 
are  WG  (window  glass)  and  WW  (water  white).  The  grades 
most  used  for  paper-maker's  size  are  F  and  G.  The  reason  for 
this  is  that,  although  the  lower  grades  give  good  water  resistance, 
they  cannot  generally  be  used  on  account  of  the  color,  while 
those  lighter  than  G  are  not  hard  and  dense  enough  to  give  the 
best  sizing.  These  grades  arc  standard,  and  the  rosin  coming  on 
the  market  in  the  Southern  States  is  inspected  and  graded  by 
Government  Inspectors. 

Quotations  are  made  in  terms  of  a  barrel  of  280  pounds,  but  the 
rosin  is  marketed  in  casks  that  have  a  gross  weight  (the  cask  and 
its  contents)  of  about  500  pounds.     Consequentl}'^,  when  purchas- 


§4  ENGINE  SIZING  25 

ing  rosin  for  use  in  paper  making,  allowance  must  be  made  for 
waste  in  breaking  up  the  containers.  The  weight  of  the  staves  is 
from  17%  to  18%  of  the  gross  weight.  The  price  of  rosin  fluctu- 
ates considerabl}^,  depending  on  the  demand  in  various  parts  of 
the  world  for  rosin  and  also  on  the  demand  for  the  turpentine  that 
is  produced  at  the  same  time  as  the  rosin, 

43.  Characteristics  and  Uses  of  Rosin. — Chemically,  rosin 
consists  chiefly  of  the  anhydride  of  abietic  acid  C44H62O4.  For 
practical  purposes,  however,  rosin  may  be  considered  as  consisting 
of  90%  to  97%  of  abietic  acid  C44H64O5,  because  the  anhydride, 
when  cooked  with  alkali,  gives  salts  (or  soaps)  in  exactly  the  same 
manner  as  abietic  acid  itself  would  do.  One  of  the  outstanding 
characteristics  of  soaps  made  from  rosin  is  their  ability  to 
emulsify  oils  and  like  materials  in  water  solutions.  It  is  this 
property  of  rosin  soap  which  makes  possible  the  use  of  size 
solutions  containing  a  quantity  of  rosin  in  excess  of  that  required 
to  combine  with  the  soda. 

Other  uses  for  this  rosin  are  in  the  manufacture  of  soap, 
linoleum,  and  varnishes,  as  raw  material  for  the  production  of 
rosin  oil,  and  as  a  constituent  for  various  plastic  compositions. 

44.  Extracted  Rosin. — In  addition  to  obtaining  rosin  direct 
from  oleo  resin,  it  may  be  obtained  by  extracting  with  solvents, 
such  as  naphtha,  the  resinous  dead  wood  of  the  Southern  pines. 
The  rosin  so  obtained  is  called  extracted  rosin,  and  its  compo- 
sition differs  from  that  made  from  pitch.  When  used  for  sizing 
papers,  it  must  be  handled  somewhat  differently  also.  Extracted 
rosin  is  quite  free  from  dirt  and  is  uniform  in  character;  but,  on 
account  of  its  dark  color,  it  is  generally  classed  as  F  rosin. 

About  14,5  pounds  of  soda  ash  is  required  to  neutralize  the  resin 
acids  in  100  pounds  of  extracted  rosin;  whereas,  about  16  pounds 
of  soda  ash  is  required  for  100  pDunds  of  gum  rosin. 

Another  class  of  recovered  rosin  is  that  obtained  from  soda 
liquors  in  the  cooking  of  resinous  woods  by  the  soda  process. 
This  rosin  is  recovered  in  the  form  of  soap,  is  dark  in  color,  has 
different  physical  properties  from  ordinary  rosin,  and  if  used 
alone,  is  not  an  efficient  sizing  material. 

45.  Soda  Ash. — Soda  ash,  or  sodium  carbonate  Na2C03, 
combines  with  rosin  to  form  rosin  soap.  It  comes  on  the  market 
in  two  varieties,  the  light  and  the  heavy,  the  light  variety  being 
the  most  convenient  for  the  manufacture  of  size.     Soda  ash 


26  LOADING  AND  ENGINE  SIZING  §4 

should  contain  58%  of  Na20;  if  any  other  percentage  is  used, 
allowance  should  be  made  for  the  difference,  since  only  the  NaeO 
takes  part  in  the  reaction.  In  some  cases,  caustic  soda  NaOH 
is  used  in  place  of  soda  ash;  it  saponifies  the  rosin  more  rapidly, 
but  it  is  more  difficult  to  handle  and  is  more  expensive. 


ALUM 


46.  Paper-Maker's  Alum. — Alum  is  the  now  commonly  used 
trade  name  for  aluminum  sulphate  Al2(S04)3l8H20,  which  is 
frequently  called  paper-maker's  alum.  Properly  speaking,  the 
term  alum  should  be  confined  to  the  double  salt  of  aluminum 
sulphate  and  potassium  sulphate  Al2(SO)3K2S04-24H20,  or  a 
similar  double  salt,  and  the  first  alum  used  in  paper  making  was 
this  double  salt,  which  can  be  obtained  in  a  very  high  degree  of 
purity.  For  this  reason,  it  is  still  used  by  some  paper  makers,  in 
spite  of  its  greater  cost;  although  this  is  probably  entirelj^ 
unnecessary,  since  very  pure  aluminum  sulphate  containing 
16.  85%  of  AI2O3  can  be  obtained.  A  grade  of  aluminum  sulphate 
is  made  which  is  practically  free  from  iron  and  other  impurities; 
but  it  is  made  by  a  special  process,  and  it  is  expensive.  The 
common  grade  of  aluminum  sulphate  contains  about  0.5%  of 
iron,  calculated  as  Fe203,  and  some  alumina  AI2O3  and  silica  Si02, 
none  of  which  are  sufficient  in  amount  to  be  injurious  to  ordinary 
grades  of  paper. 

47.  Iron-Free  Alum. — For  the  best  grades  of  paper,  the 
percentage  of  iron  in  the  alum  should  be  as  low  as  possible.  Iron- 
free  alum  is  made  from  pure  alumina  AI2O3  and  sulphuric  acid, 
whereas  the  common  grades  are  made  by  dissolving  bauxite  in 
sulphuric  acid  and  filtering  the  solution  from  the  undissolved 
residues.  The  solution  is  then  evaporated  until  it  is  reduced  to  a 
point  where  the  moisture  present  would  be  that  represented  in 
the  formula  Al203(S04)3l8H20,  after  which,  it  soHdifies,  and  is 
then  ground  and  packed  for  shipment. 

Owing  to  the  two  distinct  methods  used  for  making  the  iron- 
free  and  the  commercial  alum,  there  is  a  decisive  difference  in  the 
composition  of  the  two  products.  An  alum,  however,  having  as 
low  as  0.2%  of  reduced  iron  sulphate  should  be  good  enough  in 
color  for  the  best  papers.  Often,  more  damage  is  done  to  the 
paper  from  iron  specks  that  come  from  the  beater  bars  than  from 


§4 


ENGINE  SIZING 


27 


the  iron  in  the  alum.     Iron  may  show  up  as  rust  spots,  or  it  may 
affect  the  color  by  reacting  with  the  rosin  or  the  dyestuff. 

48.  Basic  Alumina. — Paper-maker's  alum  generally  contains 
an  excess  of  alumina  AI2O3  over  the  theoretical  quantity  to  be 
accounted  for  in  the  formula  Al203(S04).-il8H20.  This  excess 
of  alumina  is  called  basic  alumina,  although  it  is  undoubtedly  all 
combined  with  the  SO3. 

An  acid  alum  is  one  that  contains  free  sulphuric  acid.  The 
jree  acid  is  that  in  excess  of  the  amount  required  by  the  alumina, 
iron,  soda,  etc.  present. 

The  brands  of  aluminum  sulphate  on  the  market  are  generally 
basic  to  the  extent  of  0.15%  to  1  %  of  alumina;  but,  for  some  mill 
conditions,  as,  for  instance,  if  hard  water  is  used,  an  alum  of 
more  acid  characteristics  (up  to  0.5%  free  acid)  might  be  suitable. 

49.  Uniformity  of  Commercial  Alums. — In  spite  of  the 
variation  and  the  impurities  in  the  bauxites  from  which  it  is 
made,  the  commercial  aluminum  sulphate  is  well  standardized, 
and  it  is  generally  very  uniform  in  character.  Aluminum  sulphate 
was  once  made  largely  from  china  clay,  which  is  a  silicate  of 
alumina  that  contains  about  37%  of  AI2O3;  but  china  clay  does  not 
dissolve  directly  in  sulphuric  acid,  unless  it  is  previously  calcined 
in  a  very  exact  manner.  The  silicious  residue  that  is  left  when 
alum  cake  is  made  in  this  way  from  china  clay  is  generally  removed, 
as  it  has  but  little  value  for  the  paper  maker,  except  as  a  filler. 

50.  Analyses  of  Alum. — The  following  table  gives  characteristic 
analyses  of  alum  (aluminum  sulphate),  compiled  from  several 
sources:  the  table  is  from  Chemistry  of  Pulp  and  Paper  Making, 
bv  Sutermeister. 


1 

2 

3 

4 

5 

6 

7 

81 

Insoluble  in  water 

14.70 
0.12 

0.49 
16.20 
0.06 

1.34 

36.62 

45.29 

0.06 

18.81 

0.80 

0.76 

45.97 

1.03 

32.58 

0.67 

22.37 

0.59 

3.80 



45.28 
27.34 

0.18 

16.32 

0.51 

[0.4 
17.4 
trace 

0.16 

21.87 

0.40 

20.0-26.5 
12. 3-13. 0» 

Iron,  FezOs 

0.1-  0.2 

Soda,  Na20 

0.67 
36.90 
45.42 

39.2 
43.0 

0.84 
49.27 
27.46 

Sulphuric  acid,  SO3: 

Combined 

Free 

34.60 

0.40 

49.95 

29.5-31.8 
0.4-  0.1 

'  Column  8  gives  average  composition  of  alum  cake  from  clay. 
*  Soluble. 


28  LOADING  AND  ENGINE  SIZING  §4 

51.  Reaction  of  Alum  and  Rosin  Size. — When  a  solution  of 
soap,  such  as  rosin  size,  is  mixed  with  a  solution  of  aluminum 
sulphate,  the  alumina  combines  with  the  rosin  part  of  the  soap, 
and  the  soda  portion  of  the  soap  is  left  to  combine  with  the  sul- 
phuric acid  from  the  alum  solution,  forming  sodium  sulphate.  The 
combination  of  alumina  and  rosin  is  insoluble,  and  it  immediately 
precipitates  from  the  solution,  coating  anything  with  which  it 
comes  in  contact.  If,"  for  instance,  the  mixing  is  done  properly  in 
the  presence  of  pulp,  all  the  individual  fibers  of  the  pulp  are  coated 
with  this  compound  of  alumina  and  rosin. 

In  the  early  days  of  chemistry,  it  was  thought  that  the  com- 
bination of  alumina  with  rosin  formed  an  aluminum-rosin  soap; 
but  later  advances  in  chemistry  have  created  the  belief  that,  in 
addition  to  the  formation  of  this  soap,  the  precipitated  material 
may  contain  free  rosin  and  free  alumina,  the  whole  forming  a 
complex  jelly,  the  characteristics  of  which  are  modified  to  a  very 
great  extent  by  the  proportions  of  the  reacting  materials  originally 
present.  The  exact  reaction  is  still  a  matter  of  controversy.  In 
any  case,  the  result  of  the  reaction  is  a  combination  or  mixture  of 
alumina  and  rosin  that  is  precipitated,  and,  on  drying,  this 
furnishes  the  water-repellant  properties  to  the  paper. 

The  amount  of  water  resistance  imparted  to  the  paper  depends 
not  only  on  the  manner  of  combination  of  these  ingredients  but 
also  on  their  physical  properties,  which  are  influenced  by  the 
temperature,  the  state  of  dilution,  and  the  rate  of  reaction  of 
the  various  materials.  These  apparently  simple  reactions  are 
really  so  complex,  and  are  affected  by  so  many  physical  condi- 
tions, as  well  as  by  various  chemical  impurities,  that  the  more 
the  subject  is  studied  the  more  interesting  and  uncertain  it 
becomes.  The  final  result  is  also  affected  by  the  treatment  in 
the  machine  room  and  the  finishing  room. 


THE  SIZING  PROCESS 


SAPONIFICATION  OF  ROSIN 


52.  Original  Method  of  Saponifying. — The  original  method  of 
saponifying  rosin  for  use  in  sizing  followed  closely  the  general 
practice  of  soap  manufacture.  The  rosin  was  boiled  with  a 
solution  of  soda  ash,  which  contained  somewhat  more  soda  ash 
than  was  absolutely  necessary  to  combine  with  all  of  the  rosin. 


§4  ENGINE  SIZING  29 

When  fully  boiled,  the  whole  was  left  to  stand  until  the  saponified 
rosin  settled  out  to  the  bottom  and  a  weak  solution  of  alkali 
remained  on  top;  this  latter  was  then  skimmed  off,  leaving  the 
rosin  soap  ready  for  use. 

This  kind  of  size  is  still  in  use  in  many  mills,  and  it  is  the  most 
soluble  form  of  size.  It  can  be  added  in  wax  form,  directly  to  a 
cold  beater,  and  it  is  the  safest  kind  of  size  to  use,  when  there  is 
no  diluting  equipment. 

53.  Modem  Method  of  Saponifying. — In  later  times,  it  has 
become  more  common  practice  to  use  a  rosin  size  that  is  not 
completely  saponified ;  in  other  words,  one  that  contains  a  certain 
amount  of  free  rosin.  The  manufacture  of  this  size  ismuch 
simpler,  and  it  is  usually  carried  on  as  follows: 

A  steel  tank,  opened  at  the  top,  but  preferably  with  a  hood 
over  it,  is  fitted  with  steam  coils  covering  the  bottom.  Into  this 
tank  is  put  a  solution  of  soda  ash,  which  contains  from  8%  to 
16%  (by  weight)  of  soda  ash,  figured  on  the  basis  of  the  amount 
of  rosin  to  be  cooked;  the  percentage  may  be  varied,  according 
to  the  character  of  the  rosin  and  the  finished  size.  The  amount 
of  water  may  vary  from  50%  to  100%  of  the  amount  of  rosin. 
When  this  solution  is  heated  by  the  steam  coils  (or  by  the  live 
steam  if  perforated  coils  are  used)  to  the  boiling  point,  the  rosin, 
broken  up  into  small  lumps,  is  shoveled  in.  It  dissolves  quite 
rapidly  in  the  hot  soda-ash  solution,  and  gives  up  bubbles  of 
carbon  dioxide  as  the  rosin  combines  with  the  soda.  When 
all  the  rosin  is  in,  cooking  is  continued  for  from  4  to  6  hours. 
The  course  of  the  reaction  can  be  followed  by  watching  the  evolu- 
tion of  this  gas,  which  continues  to  come  up  as  long  as  there  is 
uncombined  soda  ash  present. 

Another  method  of  determining  the  completion  of  the  cooking 
is  to  observe  the  way  the  cooked  rosin  flows  from  the  end  of  a 
paddle  that  has  been  dipped  in  it.  While  being  cooked,  it  runs 
off  the  paddle  in  long  strings;  but  when  the  cooking  is  complete, 
it  breaks  off  sharply. 

Still  another  method  for  testing  the  size  is  to  take  a  pint  of 
size,  mix  thoroughly  with  a  quart  of  hot  water,  thin  with  cold 
water  until  pail  is  almost  full  and  examine  for  lumps,  grains,  and 
sticky  particles  of  free  rosin.  The  cooking  should  be  continued 
until  the  test  shows  that  the  size  may  be  diluted  as  above  into 
a  homogeneous  milk,  free  from  these  indications  of  raw  or  poorly 
emulsified  rosin. 


30 


LOADING  AND  ENGINE  SIZING 


§4 


54.  To  Make  Soap  Containing  a  Definite  Per  Cent  of  Free 
Rosin. — The  amount  of  soda  ash  used  in  cooking  the  rosin 
determines  the  percentage  of  free  rosin  in  the  finished  size.  As 
an  approximate  guide  to  the  manufacture  of  size  containing 
various  percentages  of  free  rosin,  the  following  table,  which 
shows  the  results  of  the  action  of  various  percentages  of  soda  ash 
on  the  rosin,  may  be  used.  The  table  is  calculated  for  a  rosin 
having  an  acid  value  that  will  neutralize  16%  its  weight  of  sodium 
carbonate,  leaving  8.8%  of  rosin  that  will  not  saponify  in  aqueous 
solution. 

Saponification  Table 


Rosin 

NajCOs 

Rosin  soap 

Free  rosin 

Total  size 

(pounds) 

(pounds) 

(pounds) 

(pounds) 

(pounds) 

100 

16 

97.8 

8.8 

106.6 

100 

14 

85.5 

20.2 

105.7 

100 

12 

73.3 

31.6 

104,9 

100 

10 

61.1 

43.0 

104.1 

100 

8 

48.9 

54.4 

103.3 

This  table  can  be  corrected  for  any  rosin  that  has  a  different 
saponifying  value;  and  since  it  is  based  on  100  pounds  of  rosin, 
the  values  in  the  several  columns  maj^  be  considered  as  per  cents 
instead  of  pounds,  if  so  desired.  The  first  four  rows  give  formulas 
for  making  the  rosin  sizes  in  general  use.  The  first,  in  which  16  % 
of  soda  ash  is  used,  will  make  a  so-called  neutral  size,  which  is 
easily  dissolved;  perhaps  20%  to  25%  of  the  mills  in  America 
still  use  this  size  and  believe  that  it  suits  their  conditions.  A 
size  cooked  with  14%  soda  ash,  having  a  total  free  rosin  content 
of  20%,  is  a  tj'pe  of  size  quite  commonly  used;  it  is  called  mill 
size.  The  size  cooked  with  12%  soda  ash  and  holding  about  30% 
of  free  rosin,  is  another  type  quite  largely  sold  to  mills  having 
diluting  systems.  The  size  cooked  with  10%  of  soda  ash,  contain- 
ing 43%  of  free  rosin,  is  a  type  used  only  in  those  mills  having 
special  systems  for  handling  a  high  free-rosin  size.  The  cooking 
may  be  done  in  the  paper  mill,  or  the  mill  may  buy  the  prepared 
size. 

55.  Tanks  for  Cooking  Rosin. — The  size  of  the  tank  for  cooking 
rosin  should  be  at  least  double  that  necessary  to  contain  the 


§4 


ENGINE  SIZING 


31 


finished  size,  because  of  the  froth  that  rises  up  during  cooking; 
hence,  the  tank  will  overflow,  unless  it  has  sufficient  capacity. 
In  the  open  size  boiler,  Fig.  9,  provision  is  made  for  the  froth  to 
flow  back  into  the  tank  A  through  the  by-pass  B;  C  is  a,  steam 
coil. 


Fig.  9. 


Fig.  10. 


In  the  modern  American  size  cooker  (patented)  shown  in  Fig. 
10,  a  truncated  conical  surface  B  is  suspended  over  the  coils  C 
The  circulating  action  through  the  cone  is  so  rapid  that  the  size 
can  be  cooked  violently  and  rapidly  without  boiling  over. 

56.  There  is  another  method  of  cooking  which  has  been 
advocated  in  the  past  and  is  still  sometimes  used.  The  size  is 
cooked  in  a  closed  tank,  with  indirect  steam  under  pressure, 
either  with  or  without  an  agitator.     In  Fig.  11,  ^  is  a  pressure 


32 


LOADING  AND  ENGINE  SIZING 


size  cooker,  equipped  with  an  agitator  B,  steam  coil  C,  water 

inlet  H,  manhole  M,  and  size  outlet 
.V.  Instead  of  using  coils,  the  lower 
half  of  a  cooker  is  sometimes  enclosed 
in  a  steam  jacket. 

When  cooking  in  this  manner,  the 
temperature  can  be  brought  to  a 
point  considerably  higher  than  when 
cooking  in  an  open  tank;  but  the 
circulation,  and  the  consequent  uni- 
formity of  the  finished  size,  is  liable 
to  be  faulty,  unless  a  special  agitator 
is  used.  Under  suitable  conditions, 
the  size  can  be  cooked  under  pressure 
in  less  than  2  hours;  in  the  open 
tank,  from  3  to  6  hours  are  required. 
In  former  times,  it  was  the  practice 
to  use  an  open  tank,  with  direct 
steam,  and  this  required  boiling  from 
Fig.  11.  6  to  8  hours. 


QUESTIONS 

(1)  State  briefly  the  principles  underlying  the  use  of  rosin  sizing. 

(2)  (a)  How  is  rosin  obtained  and  graded?     (b)  What  grades  are  used  for 
sizing? 

(3)  WTiat  is  meant  by  the  term  saponified? 

(4)  Give  the  chemical  name,  the  molecular  formula,  and  the  character- 
istics of  soda  ash. 

(5)  (a)  Give  the  common  name  for  aluminum  sulphate.     (6)  When  is  this 
substance  acid?  (c)  when  is  it  basic? 

(6)  Explain  the  process  of  cooking  a  batch  of  rosin  size. 

(7)  How  much  soda  ash  should  be  used  for  100  lb.  of  rosin  to  make 
a  size  having  about  30%  free  rosin? 

(8)  By  what  signs  can  it  be  determined  when  the  cooking  of  size  is 
finished? 

DILUTING  SIZE 


57.  Reason  for  Diluting  Size. — One  of  the  critical  operations 
in  connection  with  the  sizing  process  is  that  of  diluting  the  thick 
size,  or  wax.  In  the  case  of  neutral  size,  this  operation  is  not  so 
important,  since  the  size  is  then  soluble  in  water  to  such  an  extent 


§4  ENGINE  SIZING  33 

that  it  is  generally  added  thick  to  the  beaters,  without  previous 
dilution.  The  case  is  different,  however,  when  size  containing 
free  rosin  is  being  used.  The  object  then  is  so  to  dilute  the  thick 
size  as  to  make  an  emulsion  of  such  a  character  that  the  free 
rosin  is  as  reactive  as  possible.  If  this  be  not  done,  the  separated 
rosin  can  produce  lots  of  trouble  on  the  paper  machine.  When 
the  dilution  is  so  carried  out  that  the  rosin  inj^the  emulsion  formed 
is  practically  entirely  invisible,  it  is  then  in  the  most  reactive 
state.  An  emulsion  in  this  condition  contains  the  rosin  in  such 
fine  particles  that  the  whole  forms  what  is  known  as  a  colloidal^ 
solution.  When  alum  is  added  to  such  a  solution,  all  the  rosin  is 
precipitated  as  though  a  neutral  size  were  used;  except  that  the 
precipitate  formed  contains  a  larger  proportion  of  rosin  and  less 
soda,  which  gives,  generally,  a  more  water-repellant  coating  to 
the  fibers.  If  the  free  rosin  is  not  invisible  in  the  diluted  solution, 
but  appears  very  white  and  milky,  the  free  rosin  is  in  suspension, 
and  it  is  not  in  a  chemically  reactive  state.  These  rosin  particles 
precipitate  when  the  neutral  soap  in  the  solution  is  coagulated 
by  alum,  but  the  precipitate  consists  of  small  particles  of  rosin 
imbedded  in  the  rosin-alumina  complex.  The  sizing  qualities 
of  this  mixture  will  vary  with  the  coarseness  and  the  amount  of 
the  rosin  particles.  The  best  sizing  result  can  be  obtained  with 
the  more  chemicallj'^  active  emulsions,  when  other  conditions 
are  properly  adjusted. 

58.  Free-Rosin  vs.  Neutral-Rosin  Sizing. — It  maj^  here  be 

remarked  that  there  has  raged,  for  some  j^ears  past,  a  very 

sharp  controversy  as  to  the  merits  of  free-rosin  sizing  as  against 

neutral-rosin  sizing;  and  manj^  arguments,  more  or  less  correct, 

have  been  advanced  in  favor  of  one  or  the  other.     The  advocates 

of  the  neutral  size  claim  that  the  sizing  is  due  to  a  resinate  of 

alumina;  those  advocating  free-rosin  size  claim  that  the  sizing 

is  due  to  the  free  rosin,  and  that  the  resinate  of  alumina  has  no 

effect.     From  the  consideration  of  the  physical  chemistry  of 

colloidal  gels,  it  appears  that  the  coating  which  furnishes  the 

sizing  qualities  is  a  complex  mixture,  which  consists  of  rosin, 

resinate  of  alumina,  and  alumina,  and  that  no  single  one  of  these 

can  be  considered  as  being  alone  responsible  for  the  sizing  result. 

By  both  theory  and  practice,  it  is  found  that  the  characteristics 

of  this  gel,  or  coating,  can  be  altered  considerably  by  varying 

^  A  colloidal  solution  is  jelly  like,  in  that  the  particles  are  held  in  suspension 
in  solution,  and  do  not  separate  from  the  liquid  in  which  they  are  suspended. 


34  LOADING  AND  ENGINE  SIZING  §4 

the  conditions  under  which  it  is  formed,  and  also  by  varying  the 
amount  and  character  of  the  free  rosin  in  the  size  emulsion.  It 
is  only  when  these  factors  are  adjusted  to  the  mill  conditions 
that  the  most  efficient  results  can  be  obtained. 

It  cannot  be  said,  however,  that  solutions  of  size  containing 
free  rosin  are,  on  that  account  only,  more  efficient  than  neutral 
sizes;  but  it  can  be  affirmed  that  when  the  free  rosin  is  in  a 
reactive  state  and  properly  utilized,  the  free  rosin  size  can  be 
made  to  give  more  efficient  results  than  the  neutral  size.  Bear- 
ing this  in  mind,  therefore,  the  methods  used  in  diluting  sizes 
containing  free  rosin,  which  is  the  kind  of  size  used  in  most 
mills  at  the  present  time,  will  now  be  discussed. 

59.  Methods  of  Diluting  Size. — A  size  containing  approxi- 
mately 20%  of  free  rosin  can  be  diluted  to  make  a  fairly  stable 
emulsion  in  moderately  warm  water;  in  man}^  cases,  a  size  of  this 
constitution  is  added  directly  to  the  beater.  It  is  unsafe  to 
attempt  to  dilute  a  size  containing  more  than  20%  free  rosin 
by  adding  it  directly  to  the  beater;  for,  if  conditions  are  not 
just  right,  some  of  the  particles  may  adhere  to  one  another  and 
form  particles  of  rosin  sufficiently  large  to  show  up  as  rosin  spots 
in  the  finished  paper. 

The  proper  method  of  using  higher  free  rosin  size  is  to  dilute  it 
to  an  emulsion  containing  approximately  2%  of  rosin,  and  then 
add  this  emulsion  to  the  beater.  This  dilution  is  generally 
accomplished  by  adding  thick  size  to  hot  water,  with  violent 
agitation.  This  may  be  effected  by  blowing  the  size  into  a 
tank  of  hot  water  in  a  fine  stream  jet,  or  by  adding  it  in  small 
quantities  and  stirring  violently  at  the  same  time.  When  first 
made,  such  an  emulsion  is  of  fairly  good  character,  provided  the 
agitation  has  been  sufficiently  violent  and  the  size  has  not  been 
added  too  quickly.  Unfortunately,  however,  an  emulsion  of  this 
character,  when  hot,  tends  to  destroy  itself  as  an  emulsion,  owing 
to  the  fact  that  the  rosin  particles  agglomerate,  and  the  emulsion 
gradually  becomes  more  and  more  milky.  If  kept  hot  for  a 
sufficient  length  of  time,  the  particles  will  become  so  large  as  to 
settle  from  the  emulsion,  leaving  the  remainder  of  less  value. 
By  chilling  the  partially  diluted  size  with  cold  water,  this 
difficulty  might  be  avoided;  but  it  is  hard  to  do  this  without 
causing  further  decomposition. 

By  using  a  S3'stem  of  graduated  dilution,  a  better  emulsion 
can  be  obtained.     This  is  accompfished  by  first  diluting  the  size 


§4  ENGINE  SIZING  35 

to  a  consistency  of  about  25%  solids,  and  then  adding,  at  a 
boiling  temperature,  a  certain  number  of  parts  of  water,  the 
amount  of  which  will  vary  in  accordance  with  the  free  rosin 
content  of  the  size.  After  the  size  has  been  diluted  to  this  stage, 
and  it  will  rapidly  disperse  in  cold  water. 

Suggestions  have  been  made  at  various  times  that  other 
substances  might  be  added  to  the  hot  water,  or  to  the  size,  which 
would  act  in  such  a  manner  as  to  protect  the  size  particles  from 
this  tendency  to  agglomerate  into  larger  ones.  Substances 
having  this  property  are  known  as  protective  colloids,  and  they 
include  many  materials  of  a  gelatinous  character.  The  addition 
of  these  substances  has  a  very  definite  efTect;  but  the  advantage 
to  be  derived  depends  upon  the  material  used  and  upon  the 
conditions  under  which  the  sizing  is  done. 

The  disadvantage  from  the  use  of  these  materials  is  the  fact  that 
a  tendency  to  froth  is  often  produced,  and  more  coloring  matter 
may  be  introduced,  which  will  effect  the  brightness  of  the  paper 

60.  Diluting  System. — There  are  two  well-standardized  sys- 
tems for  diluting  a  thick  size.  In  one  of  these,  the  process 
consists  of  mixing  the  thick  hot  size  with  a  small  quantity  of 
hot  water,  at  a  definite  temperature,  within  an  injector,  and 
violently  agitating  the  size  and  water,  at  the  moment  they  mix, 
by  means  of  steam  pressure,  which  is  applied  to  the  hot  water 
from  a  jet  of  steam.  An  instantaneous  solution  is  accomplished 
in  this  way;  and  its  physical  character  is  preserved  by  using  the 
same  pressure  of  steam  to  blow  the  mixture  into  a  large  amount 
of  cold  water,  which  immediately  stabilizes  the  emulsion.  An 
emulsion  that  may  contain  as  much  as  50%  free  rosin  can  be 
made  into  what  is  practically  a  purely  colloidal  solution  having 
the  maximum  sensitiveness  to  reagents,  such  as  alum.  Fig.  12 
shows  the  arrangement  of  this  system,  the  lettered  parts  being 
as  follows : 

A  and  B  are  barrels  of  rosin;  C  is  a  cooking  tank,  heated  by 
steam  pipe  D;  £  is  a  measuring  tank;  F  is  the  heating  coil;  F  is 
the  emulsion  tank;  H  is  a  device  for  mixing  heated  rosin  soap  from 
E  with  water  from  Y  (through  pipe  L)  and  steam  from  T,  which 
injects  the  mixture  into  Y;  ^V  is  a  connection  for  supplying  water 
during  emulsification;  and  Tt:  is  a  storage  tank. 

61.  The  other  diluting  system,  illustrated  in  Fig.  13,  consists, 
essentially,  of  a  steam  injector,  so  designed  that  the  hot  size 


36 


LOADING  AND  ENGINE  SIZING 


§4 


flows  from  heated  measuring  tank  A  into  the  injector  B;  from  B, 
it  is  forced  by  means  of  a  steam  jet  from  steam  pipe  C  into  hot 


Fig.  12. 


water  in  D,  and  some  cold  water  is  finally  added  through  E. 
F  is  a,  perforated  steam  coil,  which  heats  the  contents  of  D  and 
assist  in  mixing.     Details  of  the  injector  are  shown  at  (6). 


Fig.  13. 


62.  A  later  development  of  this  method  consists  of  a  pressure 
tank  holding  hot  size,  from  which  it  is  forced  under  pressure 
directly  into  a  tank  containing  hot  water.     This  process  has 


§4  ENGINE  SIZING  37 

some  advantages  over  the  steam  injector;  but  here,  also, 
there  is  not  much  control  over  the  operation.  It  is  being 
operated  generally  with  a  size  carrying  from  25%  to  30% 
free  rosin. 

Two  other  methods  are  still  used  occasionally:  One  is  to  drop 
the  hot  size  directly  from  the  cooker  into  a  tank  containing 
twice  as  much  hot  water,  which  is  stirred  by  an  agitator;  when 
completely  mixed,  cold  water  is  run  in  and  mixed  until  the 
correct  volume  is  obtained.  The  other  is  to  feed  the  hot  size 
along  with  hot  water  into  a  fan  pump,  from  which  it  is  dis- 
charged into  a  diluting  tank.  Either  of  these  methods  may  be 
used  with  a  size  carrying  25%  or  less  of  free  rosin. 

63.  Handling  Diluted  Size. — As  it  is  seldom  possible  to  use  the 
size  immediately  after  it  is  diluted,  it  becomes  necessary  to  store 
it  until  the  stock  is  ready  to  receive  it.  Most  mills  prefer  to 
keep  a  fairly  large  supply  of  diluted  size  emulsion  on  hand;  this 
is  generally  kept  in  large  tanks,  the  capacity  of  which  depends 
on  the  amount  being  used  daily  in  the  plant.  About  one  day's 
supply  is  the  amount  usually  kept  for  this  purpose,  though  the 
amount  thus  stored  may  be  varied,  being  greater  or  less,  to  suit 
the  working  conditions  of  the  mill.  A  well-made  emulsion  will 
keep  quite  well  at  ordinary  temperatures  for  a  considerable 
time. 

64.  Effect  of  Hard  Water. — The  water  used  in  diluting  the 
size  should  be  as  soft  and  pure  as  possible.  As  a  general  rule, 
however,  it  is  impossible  to  obtain  absolutely  pure  water;  and  a 
certain  degree  of  deterioration  in  the  emulsion  must  be  expected, 
on  account  of  the  salts  dissolved  in  the  water.  These  salts  act 
in  a  manner  somewhat  similar  to  alum,  and  they  precipitate  a 
portion  of  the  size.  The  salts  of  lime  and  magnesia  form 
insoluble  soaps  (resinates),  which  produce  a  thick  scum  on  the 
emulsion  tank.  This  is  merely  a  verification  of  what  happens 
when  the  size  is  discharged  into  a  beater  full  of  hard  water; 
it  explains  why  it  is  necessary  for  a  mill  using  hard  water 
to  increase  the  amount  of  alum  in  order  to  get  the  lime  out  of 
the  way. 

Salts  such  as  sodium  chloride,  sodium  sulphate,  and  other 
salts  of  the  monovalent  elements,  are  almost  equally  detrimental; 
if  they  are  sufficiently  concentrated,  they  will  tend  to  break  up 
the  emulsion  and  slowly  coagulate  it.     They  displace  the  rosin 


38  LOADING  AND  ENGINE  SIZING  §4 

soap    in    the    solution,    because    they    are    themselves    more 
water  soluble. 

65.  Furnishing  the  Beater. — In  mills  using  diluted  size  as 
above  described,  it  is  the  general  practice  to  pump  the  diluted 
size  from  the  storage  tanks  to  the  beaters.  For  measuring  the 
size  at  the  beater,  a  tank  should  be  placed  either  over  the  beater 
or  somewhere  near  and  hand}'  to  it;  and  it  should  be  equipped 
with  a  gauge  that  is  graduated  to  show  the  amount  of  rosin  per 
inch  of  depth  of  the  measuring  tank.  The  graduation  of  this 
gauge  may  be  simply  in  inches,  or  in  pounds  of  rosin,  or  in 
terms  of  some  unit  to  which  the  mill  has  become  accustomed, 
such  as  a  pail  or  a  dipper.  Some  prepared  rosins  are  added 
directly  to  the  beater,  and  directions  call,  usually,  for  so  many 
dippers. 

All  these  methods  are  in  use;  but  it  would  seem  that  the  most 
logical  procedure  would  be  so  to  graduate  the  measuring  tank 
that  the  number  of  pounds  of  rosin  for  a  given  volume  could  be 
stated  definitely.  It  is  frequently  possible  to  use  one  measuring 
tank  for  a  pair  of  beaters,  if  they  are  close  together.  These 
tanks  should  have  a  wash-out  connection  for  cleaning. 

66.  Adding  Alum. — While  alum  may  be,  and  frequently  is, 
added  to  the  beater  in  ground  form,  it  is  considered  better 
practice  to  dissolve  the  alum  first  and  add  it  in  the  form  of  a 
concentrated  solution.  Alum  solutions  are  very  corrosive  to 
iron;  they  should  not  be  handled  in  anything  but  wooden  pails, 
and  should  be  stored  or  contained  only  in  wooden  or  concrete 
tanks  having  bronze  fittings.  Concrete  tanks  for  holding  alum 
must  be  specially  prepared  and  treated,  to  resist  the  corrosive 
action  of  this  acid  salt. 

The  common  form  of  an  alum-diluting  system  consists  of  a 
wooden  tank,  with  an  agitator;  this  is  worked  on  the  batch 
(intermittent)  system,  and  is  used  to  dissolve  ground  alum.  The 
cheapest  method  is  to  buy  the  alum  in  large  cakes,  and  to  keep  a 
large  tank  (without  agitator)  filled  with  these  cakes.  The 
tank  is  also  kept  filled  with  water;  and  a  fairly  strong  solution 
can  be  taken  from  the  bottom,  the  density  of  which  will  vary 
with  the  temperature  of  the  water  and  the  length  of  time  of 
contact.  Some  mills  use  two  tanks  equipped  alike,  one  being 
used  as  a  storage  tank  while  alum  is  being  dissolved  in  the  other. 
The  solution  is  kept  uniform. 


§4  ENGINE  SIZING  39 

PROPORTIONS  OF  SIZE  AND  ALUM  AND   ORDER   OF    FURNISH 

67.  Complexity  of  Reactions. — The  problem  of  sizing  is 
extremely  complex.  Different  reactions  take  place  between  the 
rosin  and  the  aluminum  sulphate,  which  depend  on  the  amount 
by  which  the  aluminum  sulphate  exceeds  the  amount  actually 
needed  to  react  with  the  rosin  soap.  When  no  other  factors 
intervene,  a  definite  ratio  may  be  determined  for  a  size  having  a 
fixed  percentage  of  soap  and  for  certain  mixing  conditions.  The 
whole  reaction  is  made  uncertain  by  the  presence  of  other 
reactive  salts,  which  are  either  in  the  water  or  in  the  stock;  and 
these  salts  are  of  such  a  complex  character  that  no  definite 
formulas  can  be  given  that  will  apply  to  every  case. 

As  a  general  rule,  the  size  goes  into  the  beater  before  the  alum ; 
but  there  are  cases  where  there  are  so  many  injurious  reactions 
lying  in  wait  for  the  size  that  it  suffers  less  injurj^  by  going  in 
last.  Where  hard  water  is  used,  it  may  be  advisable  first  to  add 
enough  alum  to  take  care  of  the  hardness. 

68.  Amount  of  Alum  Required. — A  general  idea  of  how  the 
size  and  alum  react  on  each  other  can  be  obtained  by  assuming 
that  no  impurities  are  in  the  paper  stock  or  in  the  water  that 
contains  it.  Also,  that  the  size  and  alum  have  both  been 
properh-  diluted,  and  that  soft  water  is  used  in  furnishing  the 
beater,  which  is  not  heated.  Under  these  conditions,  it  may  be 
stated  that  a  size  containing  from  35%  to  45%  of  free  rosin 
would  require  about  15  pounds  of  alum  for  every  10  pounds  of 
rosin. 

Under  similar  conditions,  a  size  having  from  20%  to  25%  of 
free  rosin  should  require  about  20  pounds  of  alum  for  every  10 
pounds  of  rosin  used;  and  a  size  that  is  fully  saponified  and 
alkaUne  might  require  30  pounds  of  alum  for  every  10  pounds  of 
rosin  used,  to  produce  proper  characteristics  in  the  rosin  precipi- 
tate and  in  the  fibers. 

These  ratios  have  no  basis  in  theory,  because,  theoretically,  it 
ought  not  to  require  over  4  pounds  of  alum  for  every  10  pounds 
of  size;  but,  in  actual  practice,  the  proper  combinations  are  not 
effected  unless  the  alum  is  used  in  large  excess;  and  this  excess 
must  be  greater  the  more  there  is  of  rosin  in  the  form  of  soap. 
The  figures  given  may  be  used  as  a  guide  only.  The  right 
proportions  of  alum  and  size  must  be  determined  empirically 
for  each  mill;  and  the  proportions  will  vary  with  the  character 
of  the  stock  and  water  and  the  methods  of  reclaiming  back  water. 


40 


LOADING  AND  ENGINE  SIZING 


§4 


Difficulty  may  be  experienced  in  sizing  if  steam  is  blown  into 
the  beater,  as  is  sometimes  done  to  "free"  the  stock,  or  if  the 
stock  becomes  heated  through  beating  action. 


Per  Cen+ Alum 
I    2    3   4-    5    &  7 


150 
B5 
120 
105 
90 
75 
60 
45 
SO 


0  05  1.0  1.5  2.0  2.5  3.0  3.5  4.0  4.S  5.0 
Per  Cent  Ro&in 


2_ 


0     0.5 


,.0     1.5    2.0    2.5    3.0 
Per  Ceni- Alum 


440 
400 
360 
ilO 
280 
240 
200 

l&O 
120 

80 

40 

n 

5 

H  • 

— 

— ■ 

/ 

i< 

-^ 

/ 

4< 

/ 

// 

J 

/ 

1 

Ij 

I 

1 

1 

0    0.5     1.0     1.5    2.0    2.5    3.0 
Per  Ceni  Alum 


900 
840 
780 
720 
660 
600 
540 
480 
420" 
360 
300 
240 
180 
120 


T^ 


0     05    1.0     1.5    2.0    2.5 
Per  Cent  Alum 


3.0 


Fig.  14. 


69.  Variation  in  Water  Resistance.— The  amount  of  water 
resistance  that  can  be  obtained  in  paper  by  the  use  of  rosin  size, 
depends  upon  the  kind  of  size,  the  method  of  using  it,  the  amount 


§4  ENGINE  SIZING  41 

and  kind  of  alum  used,  the  character  of  the  pulp,  the  amount 
of  and  temperature  of  beating,  the  formation  of  the  sheet  on  the 
wire,  the  methods  of  extracting  the  water,  and  the  manner  of 
drying  and  calendering. 

It  was  stated  in  the  Section  on  Properties  of  Pulpwood,  Vol.  Ill, 
that  resins  change  on  exposure  to  sun  and  air.  This  accounts 
for  the  fact  that  paper  that  has  been  exposed  to  sunlight  becomes 
gradually  less  water  resistant. 

What  can  be  accomplished  under  good  water  and  mill  condi- 
tions, using  a  40%  free  rosin  size,  properly  diluted,  is  shown  in 
curve  No.  1,  Fig.  14,  which  was  presented  by  Paul  Bray  to  the 
Technical  Association' of  the  Pulp  and  Paper  Industry  at  New 
York,  Feb.  6,  1918.  The  curve  shows  that,  under  good  condi- 
tions, the  maximum  sizing  effect  is  obtained  with  4%  of  rosin. 
He  also  determined  the  sizing  results  when  using  a  constant 
amount  of  rosin  and  varying  the  alum.  Beginning  with  0.5% 
of  rosin  on  the  w^eight  of  paper  stock,  he  obtained  curve  No.  2 
and  other  curves,  Nos.  3  to  7,  for  each  additional  ^%  until  3% 
of  rosin  was  reached.  Thus,  for  curve  2,  the  rosin  was  constant 
at  1%;  for  curve  3,  the  rosin  was  constant  at  1.5%;  etc.  The 
ordinates  (vertical  measurements)  in  each  case  give  the  number 
of  seconds  require  for  a  standard  ink,  at  constant  temperature, 
to  penetrate  paper  floated  on  it. 

In  another  mill  using  the  same  kind  of  size  and  alum,  but 
having  different  water  and  stock  conditions,  the  curves  showing 
the  sizing  results  would  be  different  under  the  several  alum 
ratios.  If  a  size  were  used  containing  no  free  rosin  whatever, 
or  if  the  size  were  decomposed  on  diluting,  a  still  different  curve 
would  be  shown,  and  the  maximum  result  would  be  lower. 
Sutermeister  points  out  (Chemistry  of  Pulp  and  Paper  Making) 
that  loading  very  materially  reduces  the  sizing  effect.  Some 
fillers  affect  it  more  than  others. 

70.  Other  Substances  Added  to  Produce  Special  Effects. — 

There  is  no  real  substitute  for  rosin  in  sizing  paper,  but  there  are 
a  number  of  materials  that  can  be  used  with  it  to  produce  special 
effects.  One  of  these  is  sodium  silicate,  "water  glass,"  which, 
when  precipitated  with  aluminum  sulphate,  gives  a  mixture  of 
silica  and  alumina,  which  has  a  hardening  effect  on  the  paper. 

71.  Sodium  Silicate  Na^SiOs. — Sodium  silicate  is  one  of  the 
most  attractive  and,  at  the  same  time,  one  of  the  most  difficult 


42  LOADING  AND  ENGINE  SIZING  §4 

materials  to  use  as  a  sizing  ingredient.  The  properties  of  the 
siHcate  are  so  different  from  those  of  rosin  that  it  cannot  be 
considered  in  any  way  as  a  rosin  substitute;  but  it  can  be  used 
to  alter  the  characteristics  of  the  paper  and  to  modify  the  effect 
of  the  rosin  sizing.  Manj^  users  of  sodium  silicate  have  had 
unsatisfactory  results,  either  owing  to  the  method  of  using  it  or 
because  the  properties  obtained  from  it  were  not  suited  to  the 
kind  of  paper  treated. 

New  methods  of  using  sodium  silicate  that  will  extend  its 
sphere  of  usefulness  may  yet  be  developed.  It  gives  hardness 
and  stiffness  to  the  paper;  and  it  is  largely  used  by  those  paper 
manufacturers  who  are  not  able  to  get  sufficient  snap  in  their 
papers  by  other  means.  On  some  classes  of  paper,  it  will  increase 
the  Mullen  test,  but  it  will  also  reduce  the  folding  qualities. 

72.  Synthetic  Resins. — During  the  World  War,  coumarone 
resins  were  used  in  Germany.  They  could  not  be  saponified  in 
the  usual  way,  but  were  emulsified  by  means  of  rosin  soap  or 
glue.  The  production  of  a  good  synthetic  resin  has  been  the 
subject  of  much  chemical  research. 

73.  Casein. — Casein  is  sometimes  used  in  a  beater  for  a  special 
purpose,  such  as  keeping  down  fuzz,  or  for  increasing  elasticity. 
It  is  dissolved  by  treating  with  an  alkali,  and  it  is  precipitated 
by  alum  or  other  acid  in  a  manner  similar  to  rosin.  Casein  is 
relatively  expensive,  and  it  is  likely  to  give  the  paper  an 
unpleasant  odor,  unless  used  with  great  care. 

74.  Starch. — Starch  is  used  in  sizing  paper,  both  in  engine 
and  in  tub  sizing.  As  an  engine  size,  it  may  be  used  alone  or 
with  sodium  silicate.  For  tub  sizing,  a  modified,  or  thin-boiling, 
starch  is  generally  used. 

Starch  does  not  make  paper  water  resistant;  but  it  imparts  a 
certain  slickness  to  the  paper  on  calendering,  increases  the 
strength,  imparts  snap  and  rattle,  and  reduces  fuzz  on  certain 
kinds  of  stock. 

When  used  in  the  beater,  the  starch  may  first  be  swollen  and 
gelatinized  by  boiling;  or  the  raw  starch  may  be  added  directly 
to  the  beater,  which  should  be  done  early  enough  in  the  process 
to  get  thorough  mixing.  The  gelatinization  of  the  raw  starch, 
which  makes  it  effective,  is  partly  accomplished  by  the  heat  of 
the  paper  dryers. 


§4  ENGINE  SIZING  43 

INDIRECT  EFFECTS  FROM  SIZING 

75.  Color. — It  is  well  recognized  that  rosin  will  give  a  yellow- 
ish tint  to  paper,  and  this  must  be  offset  as  much  as  possible  by 
the  aid  of  blue  coloring  matter.  The  color  effect  of  rosin  becomes 
noticeable  when  over  1%  of  rosin  is  used.  Inasmuch  as  the 
higher  grades  of  rosin  are  not  the  best  for  sizing,  it  is  important, 
in  order  to  obtain  the  whitest  color  in  the  paper,  that  the  sizing 
should  be  well  done,  using  onl}'-  the  smallest  quantity  of  rosin 
possible. 

76.  Strength. — The  binding  power  of  rosin  size  in  the  paper 
fibers  is  greater  than  the  natural  adhesion  of  groundwood  or 
waste-paper  fibers  to  one  another,  but  is  less  than  that  between 
sulphite,  sulphate,  or  rag  fibers.  In  the  manufacture  of  strong 
paper,  the  sizing  problem  is  quite  important,  because  low  sizing 
efficiency  means  an  excess  of  rosin  to  get  the  sizing  standard 
required;  and  this,  in  turn,  may  reduce  the  strength  of  the  paper 
materially. 

77.  Finish  and  Retention. — The  finish  of  the  paper  often 
depends  on  the  amount  of  filling  material,  in  the  form  of  fine 
fibers  and  mineral  fillers,  that  is  retained  in  the  sheet  as  the  water 
is  drawn  from  it  in  during  its  formation  on  the  wire.  Since  it  is 
harder  to  polish  a  rough  surface  than  to  polish  a  smooth  one,  the 
fine  material  used  to  fill  the  voids  between  the  larger  fibers 
should  be  held  evenly  on  both  surfaces  of  the  paper.  When  the 
sizing  is  of  poor  quality,  more  of  the  filling  material  is  lost  through 
the  wire,  and  the  paper  is  not  only  lighter  in  weight  than  it  ought 
to  be,  but  the  wire  side  of  the  paper  is  rough,  and  it  will  generally 
show  feathering  action  when  written  on  with  ink. 

78.  Hardness. — The  hardness  of  the  paper  surface  depends 
partly  upon  the  paper  stock  and  the  treatment  in  the  beater; 
but  when  these  factors  are  constant,  the  degree  of  hardness  or 
softness  of  the  paper  can  be  varied  by  the  kind  and  quality  of 
sizing  materials  used.  A  good  quality  of  high  free-rosin  size  will 
produce  a  snap  and  hardness  in  the  paper  that  cannot  be  obtained 
b}'  the  use  of  a  neutral  or  low  free-rosin  size. 

The  use  of  glue  in  the  size  will  also  increase  the  hardness,  but  it 
is  a  more  costlj^  agent  for  this  purpose.  Glue  is  generally  used 
for  tub,  or  top,  sizing,  as  explained  in  the  Section  on  Tub  Sizing 
and  Finishing  Operations.     When  the  paper  stock  is  to  be  tub 


44  LOADING  AND  ENGINE  SIZING  §4 

sized  or  coated  it  must  not  be  so  well  sized  with  rosin  that  the 
glue  will  not  penetrate  the  paper,  or  the  coating  fail  to  adhere. 

79.  Rosin  Spots. — If  suspended  free  rosin  is  in  a  sufficiently 
soft  or  molten  condition  when  added  to  the  paper  stock,  it  will 
adhere  either  to  the  paper  fibers  or  to  the  wires  or  presses,  and 
it  will  gather  other  particles  of  rosin  until  masses  of  rosin  are 
formed.  These  masses  may  cause  translucent  spots  in  the 
paper,  or  they  may  retard  the  operation  of  the  machine.  These 
troubles  always  occur  when  improper  methods  are  used  in 
dissolving  or  diluting  a  high  free-rosin  size. 

There  are  other  rosin  spots  that  may  come  from  the  natural 
resins  and  waxes  of  the  wood;  they  ma}^  arise  from  an  unbleached 
sulphite  fiber,  or  from  mechanical  pulp  made  from  a  green, 
semi-resinous  wood.  The  pulp  pitch  is  a  softer  material  than 
colophony  rosin,  and  when  it  causes  machine  troubles,  it  can  be 
readily  recognized. 

80.  Froth  Spots. — When  the  paper  stock  has  a  tendency  to 
froth,  as  a  result  of  the  kind  of  size  used  or  of  impurities  in  the 
water  or  pulp,  and  when,  in  treating  the  stock,  there  is  a  con- 
siderable amount  of  agitation,  there  is  then  likely  to  be  an 
accumulation  of  froth  on  the  screens  and  at  the  slices  on  the 
machine.  This  froth  carries  in  the  bubble  film  a  certain  amount 
of  pulp,  which  is  liberated  when  the  foam  is  broken  down  by 
showers.  The  pulp  will  be  sticky  and  resinous,  and  if  it  gets  on 
the  machine  wire,  it  will  leave  a  dirty  splotch  on  the  top  surface 
of  the  paper. 

Froth  can  be  prevented  from  foaming  by  lack  of  agitation, 
or  it  can  be  reduced  by  altering  the  surface  tension  conditions 
in  the  rosin  size;  a  little  kerosene  is  sometimes  added  to  the 
stock  for  this  purpose,  but  it  is  injurious  to  the  sizing.  A  light 
froth  that  does  not  carry  many  pulp  fibers  will  cause  very  little 
trouble. 

QUESTIONS 

(1)  Describe  one  method  of  diluting  the  size  for  use  in  the  beater. 

(2)  How  and  when  should  size  and  alum  be  added  to  the  beater? 

(3)  What  determines  the  proportions  of  size  and  alum  required? 

(4)  What  is  the  effect  on  sizing  of  (a)  loading?  (6)  temperature  of  the 
beater? 

(5)  What  are  some  of  the  troubles  that  may  arise  from  sizing?  Suggest 
a  remedy  for  each. 


§4  ENGINE  SIZING  45 

SIZING  DIFFERENT  KINDS  OF  PAPER 

81.  Newsprint. — This  grade  of  paper  uses  the  least  amount  of 
size,  it  being  the  general  practice  at  the  present  time  to  leave 
out  the  size  altogether.  Newsprint  is  sometimes  sized,  however, 
especially  in  the  case  of  paper  produced  for  export,  because  it 
assists  in  giving  the  paper  the  best  finish  and  printing  qualities 
for  certain  kinds  of  work. 

One  way  to  improve  the  finish  and  printing  qualities  for  the 
best  grades  of  newsprint  is  to  make  use  of  the  beneficial  properties 
of  clay;  but  the  use  of  clay  is  considered  detrimental  to  speed  on 
fast-running  American  paper  machines.  In  order  to  get  a 
reasonable  retention  of  clay,  it  is  necessary  to  use  size.  The 
highest  grade  of  foreign  newsprint  may  contain  from  10%  to 
20%  of  clay;  under  American  conditions,  1%  to  5%  would  be 
more  usual,  and  this  would  apply  to  special  grades,  as  half-tone, 
rather  than  to  standard  newsprint. 

The  modern  tendency  is  to  make  newsprint  at  a  great  speed, 
and  to  mix  the  stock  in  great  tanks  or  chests,  without  beating 
or  sizing.  If  any  sizing  effect  is  required  to  be  obtained  under 
these  manufacturing  conditions,  very  dilute  solutions  should  be 
used,  and  they  should  be  carefully  prepared.  Hanging,  or 
wall  paper,  is  generally  classed  with  newsprint.  It  is  not  a 
difficult  paper  to  size. 

82.  Book  Papers. — The  engine  sizing  of  book  papers  is  depend- 
ent to  a  considerable  extent  upon  the  amount  and  kind  of  loading 
used.  Proper  sizing  standards  are  very  important;  but  the  chief 
characteristic  required  in  this  class  of  paper  is  printing  quality, 
which  is  indirectly  affected  by  the  amount  of  rosin  sizing.  A 
large  amount  of  book  paper  has  no  sizing,  but  the  average 
furnish  would  be  about  1  %  of  rosin. 

It  is  economical  to  use  rosin  in  all  well-loaded  papers,  because  of 
the  increased  retention  of  filler  that  can  be  obtained.  This 
feature  is  probably  more  important  than  the  sizing  effect,  since 
printing  ink  contains  oil  and  does  not  require  water  resistance  in 
the  paper. 

83.  Coated  Papers. — Coated  papers  or  papers  to  be  pasted 
require  that  the  degree  of  water  resistance  be  not  so  great  as  to 
prevent  some  penetration  by  the  water  in  the  coating  mixture; 
this  is  necessary  to  cause  proper  adhesion  of  the  coating  to  the 
paper. 


46  LOADING  AND  ENGINE  SIZING  §4 

84.  Bond  and  Writing  Papers. — These  papers  are  made  from 
either  sulphite  or  cotton  fibers,  or  are  from  mixtures  of  both. 
They  contain  ver\'  httle  loacUng,  and  the  results  from  engine 
sizing  depend  largely  upon  the  chemical  and  physical  properties 
of  both  the  cellulose  and  the  rosin.  The  problem  of  sizing  these 
papers  is  more  complicated  than  with  any  other  grades.  The 
stock  is  occasionally  injured  in  bleaching.  The  amount  of 
hydration  is  important,  and  this  class  of  paper  seems  more 
sensitive  to  machine  conditions.  The  problem  of  sizing  is  here 
sometimes  complicated  by  considerations  of  coloring. 

85.  Wrapping  Papers. — There  are  three  main  classes  of  wrap- 
ping paper:  kraft,  or  sulphate-fiber,  papers;  dry-finish  sulphite- 
fiber  papers;  water-finish  sulphite-fiber  papers.  In  addition, 
there  are  real  manila  papers  made  from  rope,  which  are  very 
strong,  and  bogus  manila  papers  made  chiefly  from  ground  wood, 
which  are  very  weak. 

The  kraft  wrapping  papers  and  the  groundwood  papers  are 
easy  to  size,  and  they  respond  uniforml}^  to  well-prepared  free 
rosin  solutions.  Kraft  paper  is  sized  with  from  0.5%  to  2% 
rosin.  The  lowest  amount  of  rosin  is  used  in  twisting  paper,  and 
the  highest  amount  is  used  in  tape  papers. 

86.  The  dry-finish  sulphite  papers  are  usuall}^  more  difficult  to 
size,  owing  to  variations  in  the  character  of  the  pulp,  which  does 
not  always  respond  to  sizing  reactions. 

In  water-finish  sulphite  wrapping  papers,  the  sizing  is  practi- 
cally destroyed  on  the  calenders.  It  must  be  well  sized,  however, 
when  it  leaves  the  dryers,  or  it  will  break  on  the  calenders.  The 
water  penetration  test  of  this  class  of  paper  will  be  5  to  15  minutes, 
as  it  comes  off  the  dryers,  and  20  to  100  seconds,  as  it  leaves  the 
calender  rolls. 

An  excess  of  rosin  is  injurious  to  the  strength  of  the  fiber.  The 
best  product  for  these  papers  is  made  with  hard  sulphite  and  hard 
sizing. 

87.  Wallboard. — Wallboard  is  exposed  to  conditions  where  it 
is  desirable  to  have  the  least  amount  of  expansion  and  contraction. 
The  rate  at  which  moisture  may  be  absorbed  by  wallboard  can 
be  retarded  })y  rosin  sizing,  and  the  total  amount  of  water 
absorbed  can  be  restricted  by  the  same  means. 

Although  surface  coatings  are  often  applied  to  pasted  board  to 
prevent  expansion  and  contraction,  it  has  also  been  proved  to  be 


§4  ENGINE  SIZING  47 

desirable  to  have  the  soKd  board  sized  hard  enough  to  prevent  the 
absorption  of  the  pasting  fluid. 

88.  Testboard. — This  product  is  used  for  making  containers  of 
various  kinds;  it  is  a  kraft-Hned  board,  of  which  the  hner  is  hard 
sized.  Special  difficulty  is  found  in  sizing  this  board  because  it  is 
generally  given  a  water  finish,  which  is  always  injurious  to  rosin 
sizing. 

The  paper  maker  must  maintain  a  delicate  balance  between  the 
amount  of  finish  and  the  amount  of  rosin  required,  since  the  water 
resistance  will  vary  inversely  with  the  amount  of  pressure 
applied  in  the  water  finish. 

89.  Rope  and  Grease -Proof  Papers. — Rope  stock  is  very  hard 
material  to  size,  because,  probably,  of  the  method  of  boiling  the 
stock,  the  excessive  beating,  and  the  calendering  conditions. 

Grease-proof  papers  are  always  poorly  sized,  owing  to  the 
calendering  methods  used  for  producing  the  translucency. 


LOADING  AND  ENGINE 
SIZING 


EXAMINATION  QUESTIONS 

(1)  (a)  Name  five  substances  commonly  used  as  loading  for 
paper.  (6)  State  which  are  natural  products  and  which  are 
manufactured  products. 

(2)  What  are  the  usual  impurities  in  clay,  and  why  are  they 
objectionable? 

(3)  (a)  Explain  the  purpose  of  adding  a  filler  to  paper.  (6) 
How  much  filler  is  generally  used? 

(4)  (a)  What  is  meant  by  retention  ?  (6)  What  factors  increase 
retention? 

(5)  How  may  the  fineness  of  a  filler  be  determined? 

(6)  How  is  the  amount  of  iron  in  a  filler  estimated? 

(7)  Mention  two  important  differences  between  engine  sizing 
and  tub  sizing  of  paper. 

(8)  (a)  What  is  rosin,  chemically?  (b)  Why  is  carbon  dioxide 
given  off  when  rosin  is  saponified  with  soda  ash? 

(9)  Why  is  the  amount  of  iron  in  aluminum  sulphate  important  ? 

(10)  What  happens  when  rosin  size  is  mixed  with  a  solution  of 
aluminum  sulphate  in  the  presence  of  paper  pulp? 

(11)  What  effect  does  the  amount  of  soda  ash  used  to  make 
size  have  on  the  amount  of  alum  required  in  the  beater? 

(12)  What  effect  does  hard  water  have  on  rosin  size? 

(13)  Why  is  paper  sized,  and  how  is  the  effectiveness  of  sizing 
determined? 

(14)  Name  two  substances  that  may  be  added  to  the  beater 
for  special  effects,  and  tell  what  they  do  to  the  paper. 

(15)  What  effect  has  sizing  on  color,  strength,  finish,  and  hard- 
ness of  paper? 

(16)  State  the  sizing  requirements  of  five  kinds  of  paper. 

§4  49 


SECTION  5 

COLORING 


INTRODUCTION 

Authorship:  This  Section  was  prepared  by  the  Dyestuff  Coininittee  of 
the  Technical  Association  of  the  Pulp  and  Paper  Industry — Charles  G. 
Bright,  Ross  Campbell,  C.  C.  Heritage,  Kenneth  T.  King,  Clarke  Marion, 
and  Carl  Schneider,  in  collaboration  with  Dr.  Otto  Kress. 

1.  Scope  and  Purpose  of  this  Section. — The  pleasing  appear- 
ance required  of  the  finished  paper  depends  very  largely  upon  the 
proper  manipulation  of  the  coloring  processes.  The  importance 
of  this  branch  of  paper  manufacture  is  realized  when  it  is  con- 
sidered that  fully  98  per  cent  of  the  tonnage  of  paper  produced  is 
colored  in  some  form,  ranging  from  the  tinting  of  all  types  of 
white  paper  to  the  production  of  heavy  shades  in  the  standard 
grades  and  specialties.  Past  experience  has  proved  that  efficient 
progress  in  methods  of  application  has  been  aided  by  the  coopera- 
tion of  paper  and  dyestuffs  manufacturers,  and  the  necessity  for 
such  cooperation  will  be  made  apparent  in  the  following  pages. 
It  is  the  purpose  of  this  Section  to  place  before  the  reader  such 
information  on  dyestuffs  and  their  application  to  paper  as  is 
essential  to  the  production  of  the  proper  shades  and  colors.  At 
the  same  time,  a  foundation  will  be  laid  for  the  subsequent  work 
that  will  ultimately  be  done  in  connection  with  the  general 
advancement  in  manufacturing  operations. 

While  a  knowledge  of  chemistry  and  physics  is  of  great  advan- 
tage in  studying  the  application  of  dyestuffs  to  paper,  it  is  not  as 
important  as  a  thorough  practical  knowledge  of  the  working 
qualities  of  the  individual  dyestuffs  and  of  the  stocks  on  which 
they  are  used;  consequently,  no  further  knowledge  of  chemistry 
will  be  required  than  is  contained  in  the  Section  on  Elements  of 
Chemistry,  Vol.  II,  which  the  reader  is  assumed  to  possess. 

Superintendents,  beater  engineers,  and  students  of  paper 
manufacture  should  be  familiar  with  the  properties  of  the  various 
§5  1 


2  COLORING  §5 

groups  of  dyestuffs,  the  variety  of  dyestuffs  in  each  group,  and 
the  action  of  individual  dyestuffs  during  the  process  of  coloring. 
A  practical  working  knowledge  of  the  equipment  used,  and  of 
the  different  methods  of  application  as  applied  to  various  types 
of  equipment,  should  be  acquired.  The  foregoing,  together 
with  a  short  history  of  the  dyestufT  industry,  will  form  a  nucleus 
for  a  thorough  understanding  of  this  subject,  which  should  be 
supplemented  by  practical  experience  in  the  mill. 

2.  History  of  Coloring  of  Paper. — The  coloring  of  different 
substances  has  engaged  the  attention  of  man  from  the  earliest 
ages.  Records  of  the  coloring  of  fabrics  go  back  as  far  as  the 
year  2000  B.  C,  With  the  beginning  of  manufacture  of  hand- 
made papers,  it  is  recorded  that  vegetable  stains  and  minerals 
were  used  for  coloring  purposes. 

Until  the  latter  part  of  the  nineteenth  century,  paper  was 
colored  with  pigments,  vegetable  colors,  and  lakes  (insoluble 
compounds  made  from  vegetable  colors);  but,  due  to  the  com- 
paratively few  pigment  and  vegetable  colors  produced,  the 
variety,  quality,  and  uniformity  of  shades  thus  obtained  were 
in  no  wa3^  comparable  to  those  made  possible  by  the  discovery 
of  the  aniline  dyestuffs. 

3.  Mauve,  the  first  aniline  dyestuff,  was  discovered  by  Sir 
William  Henry  Perkin,  in  1856,  in  an  attempt  to  manufacture 
synthetic  quinine  by  the  oxidation  of  aniline  oil.  Although  this 
discovery  was  quite  accidental,  it  formed  the  basis  for  the  develop- 
ment of  many  other  aniline  dyestuffs,  and  for  the  subsequent 
adoption  of  them  by  the  textile  industries.  While  the  manu- 
facture of  aniline  dyestuffs  thus  dates  back  to  1856,  their  use 
in  the  paper  industry  was  negligible  until  about  the  yesiT  1890, 
when  their  cost  of  manufacture  had  been  reduced  to  a  point  that 
permitted  their  use  in  the  manufacture  of  paper.  Between  1890 
and  1914,  there  was  a  wonderful  development  in  the  European 
dyestufT  industry,  not  only  in  the  variety  of  products  applicable 
to  paper  but  also  in  the  reduction  to  very  low  levels  of  the  cost 
to  the  consumer. 

4.  While  the  first  aniline  dycstuff  was  discovered  by  an  EngUsh- 
man,  keen  interest  was  exhibited  by  both  France  and  Germany 
during  the  early  stages  of  the  development  of  the  dyestuff 
industry.     As  time  went   on,   Germany  began   to  realize  the 


§5  INTRODUCTION  3 

importance  of  such  an  industry,  and  she  gradually  drew  ahead 
of  her  English  and  French  rivals,  due  more  to  the  active  support 
of  the  German  Government,  which  subsidized  the  young  industry, 
than  to  any  superiority  of  the  German  chemist  over  his  con- 
temporaries in  other  countries.  While  the  business  was  still  in 
its  infancy,  the  German  Government  recognized  clearly  the 
advantage  of  building  up  an  industry  that  would  yield  good 
profits  in  peace  times,  and  which  could  readil}'-  be  converted 
into  an  organization  for  the  manufacture  of  munitions  of  war. 
That  the  Germans  were  correct  in  their  successful  efforts  to 
secure  a  strangle  hold  on  the  dyestuff  and  organic  chemicals 
industries  was  amply  proved  by  the  events  subsequent  to  1914. 
Prior  to  1879,  the  Germans  had  absolute  control  of  the  dyestuff 
industry  in  the  United  States.  Although  from  that  time  to  1914, 
there  were  a  few  companies  in  this  country  manufacturing 
dyestuffs,  they  were  made  principally  from  German  intermedi- 
ates. Through  the  indulgence  of  the  Germans,  the  American 
companies  were  allowed  to  continue  operations,  but  only  to  an 
extent  by  which  the  Germans  might  benefit  through  considera- 
tions and  regulations  of  the  tariff.  Several  efforts  were  made  by 
domestic  companies  to  become  established  on  this  continent,  but 
they  could  not  compete,  on  a  scale  of  appreciable  magnitude, 
with  the  subsidized  companies  of  Central  Europe. 

The  recent  World  War,  with  its  resulting  shortage  of  dyestuffs, 
proved  the  necessity  for  the  establishment  of  a  domestic  dye 
industry.  Those  concerns  which  were  making  small  quantities 
of  a  few  dyestuffs  rapidly  expanded,  in  the  effort  to  meet  the 
abnormal  demands  caused  by  the  stoppage  of  the  European 
supply.  Many  new  companies  were  formed,  with  the  result 
that,  todaj'-,  the  American  dyestuff  manufacturers  are  able  to 
meet  the  demands  of  the  paper  industry. 

5.  Source  of  Aniline  Dyestuffs. — Aniline  dyestuffs  are  deriva- 
tives of  certain  products  obtained  from  the  distillation  of  coal 
tar.  By  subjecting  these  crude  products  or  crudes,  as  they  are 
termed  in  the  trade,  to  certain  chemical  processes,  intermediates 
are  obtained.  On  further  treatment,  the  intermediates  may  be 
converted  into  dyestuffs,  explosives,  poisonous  gases,  and  drugs 
or  pharmaceutical  preparations.  A  plant  which,  in  normal  times, 
is  devoted  to  the  production  of  dyestuffs  can  thus  be  readily 
converted  into  one  for  the  manufacture  of  various  chemicals 
used  in  warfare;  and,  at  the  same  time,  it  can  produce  the 


4  COLORING  §5 

dyestuffs  required  by  the  manufacturers.  More  important  even 
than  plant  equipment  is  the  training  of  a  large  staff  of  chemists 
and  chemical  engineers,  who  are  fitted  bj^  education  and  experi- 
ence to  carry  on  any  research  work  connected  with  the  exigencies 
of  warfare  that  they  may  face.  The  bond  is  close  between  the 
dyestuff  industry  and  the  organic  chemicals  industry-  as  a  whole. 
There  is  no  branch  of  chemical  industry  where  a  thorough  appre- 
ciation of  the  principles  of  chemistry  is  more  necessary,  or  where  a 
greater  variation  in  plant  methods  and  equipment  must  be 
employed. 

Pigments  and  many  natural  organic  dyes,  which  had  not  been 
on  market  for  several  years,  owing  to  the  scarcity  of  aniline 
dyestuffs  during  the  years  1914-1918,  inclusive,  are  now  available 
in  various  forms.  At  the  present  time,  the  paper  industry  has 
at  its  disposal  a  complete  line  of  the  aniline  dyestuffs  necessary 
for  its  use,  together  with  a  larger  volume  of  pigments  and  natural 
organic  dyes  than  were  available  before  the  war. 


DYES  AND  THEIR  PROPERTIES 


CLASSIFICATION  OF  COLORING  MATERIALS 

6.  Definitions. — Dyeing  may  be  defined  as  the  art  of  coloring 
(or  changing  the  color  of)  any  material  by  bringing  it  into  contact 
with  another  material  of  different  color  in  such  a  manner  that 
the  resulting  color  will  be  more  or  less  permanent,  not  being  easily 
altered  when  the  dyed  material  is  subjected  to  such  influences  as 
heat  or  light,  washing,  etc.  The  material  used  to  change  the 
color  of  some  other  material  is  called  a  dye  or  dyestuff.  It  is  not 
sufficient  merely  to  bring  into  intimate  contact  two  materials  of 
different  color.  For  instance,  very  finely  powdered  charcoal 
may  be  thoroughly  mixed  with  water  to  form  a  black  solution; 
into  this,  a  white  cotton  cloth  may  be  dipped  and  soaked,  thereby 
turning  the  cloth  black.  The  cloth  will  not  be  dyed,  however, 
because  by  a  thorough  washing  and  rubbing,  it  can  be  made  to 
resume  its  original  color.  To  be  truly  dyed,  the  coloring  matter 
(dj'e,  or  dyestuff)  must  adhere  or  cohere  to  the  fiber,  and  it  must 
be  more  or  less  unaffected  by  such  physical  and  chemical  changes 
as  the  material  mav  receive. 


§5  DYES  AND  THEIR  PROPERTIES  5 

If  a  material  has  been  so  colored  that  its  color  is  changed  very 
little,  if  at  all,  by  the  action  of  light,  heat,  washing,  etc.,  the  dye 
used  is  said  to  be  fast,  and  the  resulting  color  is  said  to  be  a  fast 
color;  if,  however,  the  color  changes,  usually  becoming  lighter, 
or  changing  shade,  it  is  said  to  fade. 

Some  dj^es  will  not  produce  the  desired  color  by  direct  action 
on  the  fiber — they  will  not  stick,  as  it  were.  In  such  cases, 
another  agent,  called  a  mordant,  is  used.  The  mordant  adheres 
to  the  fiber,  the  dye  adheres  to  or  combines  with  the  mordant, 
and  the  dye  thus  becomes  mordanted,  or  fixed.  A  mordant  is 
defined  as  "a  substance  which,  when  applied  to  the  fiber  in 
conjunction  with  a  dyestuff,  combines  with  the  latter  to  produce 
a  useful  color." 

7.  Three  General  Groups  of  Dyes. — Coloring  matters  are 
divided  into  three  general  groups;  namely,  aniline  dyestuffs, 
pigments,  and  natural  organic  dyes.  The  first  two  groups  will 
be  discussed  in  detail;  but  in  regard  to  the  third  group,  all  that  is 
necessary  to  say  here  is  that  the  natural  organic  dyes^  include 
logwood,  the  red  woods  (camwood,  barwood,  sanderswood, 
brazilwood,  peachwood),  madder,  cochineal,  the  j^ellow  woods 
(weld,  old  fustic,  quercitron  bark,  flavine,  young  fustic),  and 
Persian  berries.  All  these  natural  organic  dyes  require  the  use 
of  mordants,  or  other  chemical  treatment.  According  to  Regi- 
nald Brown,  F.  C.  S.,  indigo,  turmeric,  orchil,  and  catechu  are 
used  without  mordants. 

8.  Reasons  for  Using  Aniline  Dyes. — Of  the  three  groups  of 
dyes,  the  first  group  is  used  more  largely  than  either  of  the  others 
in  the  manufacture  of  paper.  Though  certain  pigments  are  used 
in  considerable  amounts,  aniline  dyes  predominate  for  the 
following  reasons:  (a)  They  embrace  a  wider  range  of  shades 
than  pigments  or  natural  organic  dyes;  also,  on  account  of  their 
great  varietj^,  they  afford  more  of  an  opportunity  for  choice 
as  regards  cost,  tinctorial  power,  brilliancy,  and  resistance  to 
various  influences,  such  as  light,  acids,  or  alkalis,  (b)  Aniline 
dyestuffs  do  not  decrease  the  strength  of  finished  paper,  as  is 
the  case  with  pigments,  (c)  They  are  easier  to  handle  in. the 
mill  than  pigments  or  natural  organic  dyes,  both  with  respect  to 
manipulation  and  to  uniformity  of  results,  (d)  With  few 
exceptions,  aniline  dyes  are  the  cheapest. 

'  None  of  these  now  are  used  much,  if  at  all,  in  the  paper  industry. 


6  COLORING  §5 

ANILINE  DYES 

9.  Classification  of  Aniline  Dyes.^ — From  the  standpoint  of 
})ractical  application,  aniline  (or  coal-tar)  dyestuffs  are  not 
classified  according  to  their  chemical  constitution,  but  are  grouped 
in  accordance  with  their  general  properties.  There  are  five  such 
groups;  namely  basic,  acid,  direct  (or  substantive)  dyestuffs, 
sulphur  colors,  and  pigments  from  vat  dyes  of  the  anthracene 
series.  Each  group  has  distinctive  chemical  and  physical  prop- 
erties relative  to  their  action  on  the  fiber  and  in  their  method  of 
application.  In  order  to  identify  a  color  by  name,  it  is  necessary 
to  know  three  things:  first,  the  trade  name;  second,  the  shade  or 
the  distinguishing  letter;  third,  the  manufacturer. 

10.  Trade  Names  and  Distinguishing  Letters. — The  trade 
name  usually  bears  a  reference  to  the  class,  properties,  chemical 
constitution,  or  color  of  the  dye,  such  as  acid  blue,  fast  red, 
methylene  blue,  etc.;  but,  in  many  cases,  it  is  simply  an  arbitrary 
name,  such  as  Auramine  or  Rhodamine,  given  to  it  by  the  dis- 
coverer or  by  the  first  manufacturer. 

No  fixed  rule  applies  to  the  distinguishing  letters  following  the 
name  of  the  dyestuff.  However,  R  usually  applies  to  a  red  shade, 
2R  to  a  still  redder  shade,  G  or  Y  to  a  yellow  shade,  B  to  a  blue 
shade,  and  X  or  Cone,  to  the  more  concentrated  brands.  Some 
form  of  the  name  of  the  manufacturer  often  prefixes  the  trade 
name,  in  certain  cases,  this  designates  their  class.  For  example, 
the  names  Du  Pont,  pontacyl,  pontamine,  and  ponsol,  of  E.  I. 
DuPont  de  Nemours  &  Co.,  signify  basic,  acid,  direct,  and  vat 
dyes,  respectively. 

11.  Basic  Dyestuffs. — Basic  dyestuffs  are  so  called  because 
they  have  a  similarity  in  their  chemical  behavior  to  such  inorganic 
bases  as  caustic  soda  (NaOH)  or  ammonium  hydrate  NH4OH. 
They  appear  on  the  market  in  the  form  of  a  salt,  such  as  the 
chloride,  acetate,  oxalate,  or  nitrate,  in  which  the  molecular 
formula  corresponds  to  (dye  base)-oxalate,  (dye  base)-chloride, 
etc.  Basic  dyestuffs  are  marketed  in  this  form  because  the  color 
base  itself  is  insoluble  in  water  and  must  be  treated  with  an  acid,  to 
form  soluble  salts;  just  as  anihne,  which  is  but  slightlj^  soluble, 
becomes  the  very  soluble  chloride  on  treatment  with  hydro- 
chloric acid. 

Basic  dyes  are  characterized  by  their  extreme  brightness  and 
great  tinctorial  power;  but,  as  a  class,  they  possess  poor  fastness 


§5  DYES  AND  THEIR  PROPERTIES  7 

to  light.  All  basic  dycstuffs  can  be  mixed  and  dissolved  with 
others  of  the  same  class ;  but  they  should  not  be  mixed  or  dissolved 
with  acid  or  direct  colors,  as  they  would  be  thereby  precipitated 
as  color  lakes.'  Not  only  would  the  color  then  be  wasted,  but  the 
precipitated  lake  would  be  apt  to  produce  color  spots  on  the 
finished  paper. 

Basic  dyestuffs  are  very  sensitive  to  hard  water,  bicarbonates 
of  lime  or  magnesia,  or  any  free  alkali.  When  an  alkali  of  this 
kind  is  present,  it  neutralizes  the  acid,  setting  free  the  insoluble 
dye  base,  which  will  appear  in  the  finished  paper  as  a  color 
spot;  50  parts  per  million  of  bicarbonates  may  give  trouble.  It  is 
for  this  reason  that  the  recommendation  is  here  made  that  acetic 
acid  be  added  before  the  dyestuff,  if  trouble  from  this  source  is 
experienced. 

When  dissolving  basic  dyestuffs,  they  should  never  be  boiled; 
they  are  best  dissolved  at  a  temperature  that  does  not  exceed 
200°F.  Upon  boiling,  there  is  a  tendency  to  hydrolyze  the  dye- 
stuff  salt,  thereby  forming  an  insoluble  base,  which  greatly 
reduces  the  coloring  power  of  the  dyestuff.  Certain  basic  dye- 
stuffs,  such  as  auramine,  basic  brown,  Victoria  blue,  should 
never  be  dissolved  at  a  temperature  exceeding  160°F. 

12.  Acid  Dyestufifs. — Acid  dyestuffs  also  appear  on  the  market 
in  the  form  of  a  salt;  they  are  so  named  because,  in  the  salt,  the 
dye  radical  takes  the  place  of  the  acid  constituents  and  gives  a 
molecular  formula  such  as  sodium-(dye  acid)  or  potassium-(dj^e 
acid). 

As  a  class,  acid  dyestuffs  have  a  lower  coloring  power  than  basic 
dyestuffs,  but  they  are  much  faster  to  light;  and  on  mixed 
furnishes,  give  more  even  dyeings  than  basic  or  direct  dyestuffs. 
Acid  dyestuffs  have  no  direct  affinity  for  cellulose  fibers ;  they  are 
merely  mordanted,  or  fixed,  to  the  fiber  by  the  presence  of  size  and 
alum. 

13.  Direct,  or  Substantive,  Dyestuffs. — The  direct,  or  sub- 
stantive dyestuffs  are  also  salts  of  color  acids,  being  differentiated 
from  the  acid  dyestuffs  by  the  fact  that  they  do  not  require  alum 
or,  when  used  in  the  textile  industry,  an  acid,  to  develop  their 
tinctorial  power.  These  dyestuffs  are  so  named  because  of  their 
affinity  for  cellulose  fibers.  As  a  class,  the  direct  dyestuffs  have 
less  tinctorial  power  than  the  basic  dyestuffs;  but,  in  all  cases,  they 

1  A  lake  is  an  insoluble  color  compound. 


8  COLORING  §5 

are  much  faster  to  light  than  the  basic  d^'es,  and,  in  some  cases, 
than  the  acid  dyes.  Some  direct  dj'estuffs  are  sensitive  to  hard 
water,  some  of  the  members  of  this  group  being  precipitated  in 
the  form  of  insoluble  lime  or  magnesia  salts. 

Direct  colors  are  best  dyed  at  about  140°F.  with  the  addition  of 
salt  (sodium  chloride)  to  exhaust  {i.e.,  absorb  or  use  up)  the  color 
more  freely.  Although  this  procedure  is  used  in  mills  making 
blotting  papers,  it  is  very  seldom  resorted  to  on  sized  papers, 
because  of  the  effect  on  the  sizing  of  the  finished  sheet.  Because 
of  their  property  of  having  a  direct  affinit}-  for  the  fiber,  even 
though  these  dyestuffs  are  generally  used  for  unsized  papers, 
the  backwaters^  in  such  cases  are  not  always  perfectly  clear: 
but  they  may  be  cleared  by  adding  a  small  amount  of  alum.  How- 
ever, alum  has  the  property  of  decidedly  deadening  the  shade  of 
all  direct  dyestuffs;  and  it  is  for  this  reason  that  the  shade  pro- 
duced with  a  particular  dyestuff  will  be  different  on  sized  and 
unsized  papers. 

14.  Sulphur  Dyestufifs. — The  sulphur  dyestuffs  derive  their 
name  from  the  fact  that  sulphur  has  a  predominate  part  in  their 
manufacture.  They  are  insoluble  in  water,  but  are  soluble  in  alka- 
line sodium  sulphide,  in  which  the  dyestuff  is  reduced.  This 
reduced  form  adheres  to  the  cellulose  fiber,  and  it  is  oxidized  upon 
exposure  to  the  air,  to  form  the  color  desired.  The  onh'  asset 
of  sulphur  dyestuffs  is  their  cheapness;  but,  with  the  exception 
of  a  very  few  isolated  cases  in  the  manufacture  of  heav}-  black 
shades,  the  decrease  in  the  initial  cost  of  the  d3'estuff  will  not  offset 
the  greatly  increased  cost  of  manipulation.  While  important  to 
the  textile  industries,  the  use  of  sulphur  dyestuffs  in  the  paper 
trade  is  practically  negligible  at  the  present  time. 

15.  Vat  Colors. — The  vat  colors  are  pigments^  that  are  prepared 
by  special  processes  from  the  aniline  dyestuffs  themselves.  These 
pigments  are,  for  the  most  part,  fast-to-light  colors  that  are  used 
almost  exclusively  in  tinting  higher-grade  white  papers.  For 
example,  ponsol  colors  for  paper  (called  indanthrene  colors  before 
the  war)  are  a  special  form  of  the  insoluble  textile  dyestuff  of 
that  name.     These  colors  are  the  fastest  known.     On  account 

1  The  water  that  drains  off  from  the  fibers  during  formation  of  the  paper 
on  the  machine  wire. 

2  A  pigment  is  a  solid  which,  on  being  reduced  to  a  powder  and  mixed 
with  a  vehicle,  can  be  used  as  a  paint  or  a  dye.  A  pigment  is  insoluble 
in  the  vehicle,  while  a  dye  is  dissolved  in  it.  IVlost  pigments  are  inorganic 
compounds.  In  coloring  paper,  they  are  sometimes  added  in  the  dry 
state. 


§5  DYES  AND  THEIR  PROPERTIES  9 

of  being  so  much  faster  to  light  than  the  majority  of  the  stocks, 
the}^  shovikl  never  be  used  in  paper  that  contains  less  than  50% 
rag  unless  certain  properties  of  the  finished  paper  must  be 
obtained ;  for,  as  will  be  shown  later,  there  is  no  need  of  using,  in 
a  paper,  dyestuffs  that  are  more  permanent  than  the  stock  from 
which  the  paper  is  made.  Other  types  of  pigment  color  made 
from  aniline  dyestuffs  include  heliopont  colors,  solar  blues,  etc. 
In  all  these  cases,  the  dyestuffs  are  used  as  pigments,  and  they 
maj^  be  thrown  into  the  beater  in  the  dry  state  or  in  water 
suspension. 

PIGMENTS 

16.  Classification  of  Pigments. — There  are  no  general  rules 
for  the  nomenclature  or  classification  of  the  various  pigments  now 
in  use  in  the  paper  industry.  Each  pigment  is  a  separate  and 
distinct  chemical  compound;  hence,  those  here  mentioned  will  be 
treated  individually. 

As  a  rule,  pigments  are  very  low  in  tinctorial  power,  and  they 
have  the  disadvantage  of  lowering  the  strength  of  the  paper  in 
which  they  are  used;  but  they  increase  the  weight  of  the  paper, 
which  is  sometimes  an  advantage.  Some  pigments  have  the 
advantage  of  very  low  cost,  and  some  are  characterized  for  special 
purposes  by  great  permanence  in  resistance  to  light  and  chemicals. 
Pigments  also  act  as  fillers  to  a  certain  extent,  giving,  in  certain 
cases,  those  special  characteristics  to  the  sheet  that  may  be 
desired  in  it. 

The  chief  types  of  pigments  used  in  the  paper  industry  are 
ochers,  siennas,  umbers,  red  or  iron  oxide,  chrome  yellow, 
Prussian  blue,  ultramarine,  sap  brown,  and  lamp  black.  Pulp 
colors,  and  certain  pigments  used  in  the  coloring  of  coated  papers, 
will  be  discussed  later. 

18.  Ochers. — Ochers  are  natural  silicates  that  contain  ferric 
oxide  or  hydrated  oxide  of  iron;  they  range  in  shade  from  yellow 
to  brown,  depending  on  the  degree  of  hydration.  Ochers  are 
marketed  as  finely  divided  powders,  the  degree  of  fineness  having 
a  direct  bearing  on  the  quality  of  the  product.  Freedom  from 
grit  is  an  important  factor  in  the  use  of  ochers. 

19.  Siennas. — Siennas  are  natural  silicates  that  contain 
manganese  oxide.  The  range  of  shade  of  the  various  siennas  is 
much  the  same  as  is  that  of  the  ochers. 


10  COLORING  §5 

20.  Umbers. — Umbers  are  complex  silicates  that  contain  a 
high  percentage  of  manganese  oxide  and  ferric  hydrate.  Umbers 
are  a  greenish  brown  in  their  natural  state;  but,  on  burning,  they 
become  a  rich,  deep  brown,  which  produces  a  desirable  brown 
shade  on  paper. 

21.  Iron  Oxides. — Red  oxide,  oxide  of  iron,  or  Venetian  red 

are  pigments  tliat  depend  on  ferric  oxide  or  ferric  hydrate  for 
their  coloring  power;  they  are  used  to  some  extent  for  the  color- 
ing of  I'cd  sheathing,  cheap  roofing,  and  a  few  paper  specialties. 
The  use  of  this  product  depends  a  great  deal  on  its  quality;  for 
high-grade  papers,  it  must  be  very  finely  divided  and  free  from 
grit.  A  great  disadvantage  to  the  use  of  these  oxides  is  the 
didling  action  on  slitter  and  cutter  knives,  and  the  weakening  of 
the  finished  sheet,  which  is  caused  by  the  excessive  loading 
required  to  obtain  shades  of  average  depth. 

22.  Chrome  Yellows.^ — Chrome  yellows  of  various  shades, 
ranging  from  a  bright  greenish  yellow  to  an  orange,  are  manu- 
factured by  mixing  lead  acetate  with  sodium  or  potassium  bichro- 
mate. Chrome  yellows  are  usually  found  on  the  market  in  the 
form  of  a  paste,  a  generally  accepted  shade  being  used  under 
the  name  of  canary  'paste.  They  can  also  be  made  directly  in  the 
beater,  by  mixing  lead  acetate  with  the  stock  and  adding  suffi- 
cient sodium  or  potassium  bichromate  to  precipitate  the  lead  as 
chromate.  Chrome  yellows  are  comparatively  fast  to  light, 
but  are  very  sensitive  to  heat  and  acids,  which  makes  it  difficult 
to  maintain  a  uniform  shade  throughout  a  run,  owing  to  variation 
of  temperature  in  different  beaters. 

23.  Prussian  Blues. — Various  Prussian  blues,  both  in  the 
soluble  and  insoluble  form,  are  used  for  coloring.  They  are 
made  by  the  precipitation  of  ferric  sulphate  with  potassium 
ferrocyanide.  The  soluble  form  of  Prussian  blue  is  obtained  by 
boiling  the  precipitate  obtained  by  the  reaction  of  ferric  sulphate 
and  potassium  ferrocyanide  in  an  excess  of  ferrocyanide  solution. 
Prussian  blue  is  an  economical  color  to  use,  and  it  possesses  ver}^ 
good  fastness  to  light.  It  has  two  disadvantages;  namelj^, 
it  is  very  sensitive  to  alkali,  and  it  appears  greenish  under  artifi- 
cial light.  Soluble  Prussian  blue  must  not  be  confused  with 
the  extensively  used  aniline  dyestuff  known  as  soluble  blue  or 
acid  blue. 


§5  DYES  AND  THEIR  PROPERTIES  11 

24.  Ultramarines. — Ultramarines  of  various  shades  of  blue, 
from  greenish  to  reddish  tone,  are  used  for  the  tinting  of  higher 
grades  of  white  papers.  They  are  soluble  silicates  of  sodium 
and  aluminum,  containing  some  sodium  sulphide,  made  by 
admixture  of  sodium  carbonate,  sodium  sulphate,  claj^,  sulphur, 
silica,  and  charcoal.  After  heating  to  a  molten  mass  and  cooling, 
the  mixture  is  finely  ground  and  washed.  Ultramarines  have 
the  decided  disadvantage  of  being  sensitive  to  acids  and  alums. 
The  so-called  alum-resisting  ultramarines  are  superior  for  use 
in  the  paper  industry.  The  greater  the  percentage  of  sulphur 
and  silica  in  the  ultramarine  the  redder  in  tone  and  the  more 
resistant  to  alum  it  becomes. 

25.  Sap  Brown. — Sap  brown,  a  brown  coloring  agent  of 
unknown  composition,  has  a  limited  use  in  cheaper  grades  of 
paper.  It  is  used  more  as  a  dyestuff  than  as  a  pigment,  due  to  the 
finely  disintegrated  state  of  its  particles  in  solution.  It  has  the 
advantage  of  being  fast  to  light,  but  it  is  sensitive  to  hard  water. 
On  account  of  its  non-uniformity,  difficulties  are  experienced  in 
maintaining  uniform  shades. 

26.  Paris  Black. — Lamp,  carbon,  or  Paris  blacks,  produced  as 
soot  by  the  incomplete  combustion  of  various  oily  organic 
compounds,  are  used  to  some  extent  for  the  production  of  gray  or 
black  papers.  Lamp  black,  when  used  in  large  amounts,  has  a 
tendency  to  streak  the  paper;  it  makes  paper  rub  badly,  and  it  is 
a  decided  nuisance  in  the  beater  room.  Due  to  its  fine  state  of 
division  and  low  density,  it  is  apt,  through  careless  handling, 
to  get  into  the  air  and  settle,  in  the  form  of  soot,  on  other 
material  in  the  beater  room;  however,  this  can  be  avoided  by 
careful  handling.  The  lamp  black  either  can  be  weighed  into  a 
paper  bag,  and  the  whole  bag  thrown  into  the  beater,  or  it  can 
be  made  into  a  paste  with  hot  water.  It  is  difficult  to  obtain 
uniform  results  with  lamp  black,  because  the  depth  of  the  shade 
depends  on  the  length  of  time  and  manner  of  beating. 


SOURCES  AND  MANUFACTURE  OF  ANILINE  DYES 

27.  Source  of  Coal  Tar  and  Crudes. — Aniline  dyestuffs  are 
manufactured  from  coal  tar,  whicli  is  a  by-product  of  gas  and 
coke  making.  The  percentage  of  coal  tar  obtained  depends  on 
the  method  of  distillation  of  the  coal.     The  average  production 


12  COLORING  §5 

from  one  ton  of  coal  is,  approximately,  12,000  cubic  feet  of  gas, 
1200-1500  pounds  of  coke,  and  120  pounds  of  coal  tar. 

28.  Crudes. — Coal  tar  contains  several  different  crudes,  the 
most  important  of  which  are  benzene,  toluene,  xylene,  phenol, 
naphthalene,  and  anthracene,  and  these  are  separated  from  one 
another  by  fractional  distillation.  Each  crude  forms  the  starting 
point  from  which  certain  intermediates  of  importance  to  the 
dyestuff  manufacturer  are  made.  The  residue,  or  pitch,  which 
is  left  after  the  crude  of  highest  boiling  point  has  been  distilled, 
is  used  for  paving,  roofing,  and  for  other  similar  purposes.  After 
separating  the  crudes  into  groups,  each  group  is  further  purified 
by  additional  distillation  or  crystallization,  and  it  is  then  ready 
to  be  used  in  the  manufacture  of  intermediates. 

29.  Manufacture  of  Intermediates. — The  coal  tar  inter- 
mediates may  be  divided  into  three  groups;  nameh',  benzene 
intermediates,  naphthalene  intermediates,  and  anthracene  inter- 
mediates, all  of  which  are  derived  by  subjecting  the  purified 
crudes  to  various  chemical  operations,  such  as  sulphonation, 
nitration,  reduction,  oxidation,  fusion,  and  condensation.  The 
yields  and  purity  of  the  intermediates  formed  during  these 
operations  are  greatly  influenced  by  temperature,  pressure, 
concentration,  and  other  factors.  By  varying  the  foregoing 
operations,  and  the  conditions  under  which  they  are  conducted, 
a  large  range  of  intermediate  compounds  is  obtainable. 

30.  Azo  Dyes. — The  scope  of  this  work  will  not  permit  of  a 
detailed  account  of  the  different  processes  entailed  in  the  manu- 
facture of  intermediates  and  dyestuffs;  but  to  exemplify  the 
nature  of  such  operations,  the  following  description  of  one  of 
the  most  important  types  of  reaction  is  given.  Most  of  the 
direct,  a  large  number  of  the  acid,  and  a  few  of  the  l^asic  dyestuffs 
are  called  azo  dyes,  because  of  the  nature  of  the  reaction  that  takes 
place  in  their  formation  from  the  crudes  into  the  finished  dyestuffs. 

31.  Diazo  Dyes. — When  a  benzene  or  naphthalene  inter- 
mediate containing  an  amino  (NH2)  group  is  treated  with 
sodium  nitrite  and  hydrochloric  acid  at  a  temperature  around 
5°C.,  a  process  known  as  diazotization  takes  place.  The  amino 
group  of  the  intermediate  reacts  with  the  nitrous  acid  in  such  a 
way  as  to  form  a  diazo  compound  (see  Section  on  Elements  of 
Chemistry,  Vol.  II,  Art.  243),  which  will  readily  unite  with  other 
intermediates,  forming  a  series  of  dyestuffs,   according  to  the 


§5  DYES  AND  THEIR  PROPERTIES  13 

substances  so  combined.  Since  there  is  an  endless  number  of 
intermediates  that  may  be  diazotized,  and  since  there  are  just  as 
many  more  with  which  the  resulting  compounds  may  combine, 
it  can  readih'  be  perceived  that  an  enormous  number  of  dye- 
stuffs  can  be  formed  by  substituting  different  intermediates. 
Proceeding  a  step  farther,  the  intermediate  with  which  the 
diazo  compound  combines  may  possess  an  amino  group  that  is 
also  capable  of  being  diazotized  and  combined  with  a  third 
bod3^  In  man}^  dyestuffs,  four  intermediates  are  thus  linked  up; 
in  some  cases  as  many  as  five  are  employed. 

32.  Manufacture  of  Vat  Colors. — While  the  vast  majority  of 
basic,  acid,  and  direct  dyestuffs  are  made  from  benzene  and 
naphthalene  intermediates,  the  vat  colors  are  made  from  the 
anthracene  intermediates  by  certain  processes  of  sulphonation, 
causticization,  fusion,  etc.  These  are  the  most  difficult  dye- 
stuffs  to  manufacture,  because  very  slight  variations  in  manu- 
facturing conditions  produce  entirely  different  results.  The 
vat  dyestuffs  are  so  ca'led  because  they  must  be  reduced  in  an 
alkaline  solution  before  applj^ing  to  the  cellulose  fibers.  Since 
the}'  are  the  fastest  to  light  of  all  known  dyestuffs,  and  since 
reduction  is  not  possible  during  the  manufacture  of  paper,  these 
colors  are  prepared  in  a  special  form  for  the  use  of  the  paper 
industry-  by  reducing  to  the  leuco-compound  (or  colorless  form) 
in  an  alkaline  solution  with  caustic  soda  and  glucose,  at  high 
temperature,  and  re-oxidizing  in  the  air,  to  form  pigments  of  a 
very  fine  degree  of  subdivision. 


STANDARDIZATION  OF  DYESTUFFS 

33.  Importance  of  Standardization. — More  important  to  the 
consumer  of  dyestuffs  than  the  details  concerning  their  manu- 
facture is  the  standardization  of  the  finished  product.  In  order 
to  color  the  paper  uniformly,  the  beater  engineer  must  decrease 
the  number  of  variables  with  which  he  has  to  contend.  He 
must  be  assured  that  when  he  has  once  secured  a  color  formula 
for  a  given  furnish,  every  barrel  of  the  dyestuff  he  receives  under 
a  given  name  or  designation  shall  be  absolutely  uniform  with 
respect  to  strength  and  shade. 

34.  Methods  of  Standardization. — In  the  manufacture  of 
paper,  it  is  a  physical  impossibility  to  hold  the  basis  weight 


14  COLORING  §5 

absolutely  constant;  likewise,  in  the  manufacture  of  dyestuffs, 
it  is  impossible  for  every  run  of  the  crude  dyestuff  to  be  of  exactly 
the  same  strength  and  shade.  For  this  reason,  a  standard  of 
strength  and  shade  for  each  individual  dj^estuff  is  adopted  by 
the  manufacturer,  the  strength  of  this  standard  being  slightly 
less  than  the  average  strength  obtainable  in  the  crude  product, 
or  crude  charges,  as  they  are  called.  All  dyestuffs,  after  being 
filtered  and  dried,  are  ground  to  a  fine  state  of  subdivision,  and 
are  compared  in  strength  and  shade  with  the  standard  adopted 
by  the  manufacturer.  One  charge,  for  instance,  may  be  slightly 
Tedder  than  the  standard,  while  the  next  may  be  slightly  greener; 
different  lots  are  mixed  together  with  varying  amounts  of  the 
standardizing  agent,  to  produce  the  finished  dj^estuiT,  which  is 
exactly  the  same  in  strength  and  shade  as  the  standard  adopted 
by  the  manufacturer. 

35.  Standardizing  Agents. — The  standardizing  agent  most 
used  for  basic  dyestuffs  is  dextrine,  while  common  salt  NaCl  or 
Glauber's  salt  Na2SO4.10H2O  is  used  for  acid  and  direct  dyestuffs. 
Other  standardizing  agents  used  in  isolated  cases  are  sugar,  sodium 
phosphate,  and  soda  ash.  An  erroneous  impression  prevails 
among  certain  consumers  that  dyestuffs  containing  any  of  the 
chemicals  just  mentioned  are  more  or  less  adulterated.  How- 
ever, a  little  reflection  will  show  that  this  is  the  only  way  by  which 
the  absolute  uniformity  of  every  product  can  be  controlled  by 
the  dyestuff  manufacturers,  and  that  the  selection  of  a  standardiz- 
ing agent  is  so  made  as  not  to  interfere  with  any  subsequent 
operations  of  paper  manufacture. 

36.  Reduced  Brands. — The  practice  of  adding  a  standardizing 
agent  to  the  dyestuff  is  sometimes  abused  by  unscrupulous  con- 
cerns, which  make  large  profits  by  reducing  the  strength  of  the 
standard  brands  of  the  manufacturers;  this  is  one  cause  for  the 
excessive  number  of  dyestuffs  of  varying  concentrations  and 
shades  on  the  market,  and  it  results  in  a  great  deal  of  confusion 
to  the  consumer.  These  are  known  as  reduced  brands;  and 
whenever  such  dyestuffs  are  placed  on  the  market,  a  definite 
comparison  of  their  strength  with  that  of  the  concentrated  brands 
of  standard  manufacturers  should  be  given.  In  certain  cases, 
reduced  brands  work  more  efficiently  in  the  mill  than  the  con- 
centrated brands,  especially  where  small  quantities  must  be 
weighed.     An  example  of  this  is  the  case  of  rhodamine  B  extra 


§5  DYES  AND  THEIR  PROPERTIES  15 

and  rhodamine  B,  the  former  being  five  times  the  strength  of  the 
latter.  The  latter  is  more  generally  used  in  the  paper  industry, 
because  of  the  great  strength  of  the  rodamine  B  extra,  which 
makes  the  weighing  of  the  concentrated  form,  in  tinting  white 
papers  or  for  shading,  practically  impossible,  within  the  degree 
of  accuracy  that  must  be  maintained.  Until  the  reliability  of 
the  source  of  supply  is  established,  laboratory  tests  should  be 
made  on  the  product  samples  submitted  and,  also,  on  all  supplies 
of  dj'cstuffs  received. 

37.  Mixtures  of  Dyestuffs. — Mixtures  of  dyestuffs  are  made 
by  all  dyestuff  manufacturers,  and  they  are  sold  to  the  trade 
under  either  a  given  name  or  under  a  mixture  number.  They 
are  made  by  combining  two  or  more  dyestuffs  to  produce  a 
particular  shade,  by  mixing  them,  together  with  a  standardizing 
agent,  in  a  standard  mixer.  Efficient  paper-mill  practice  has 
proved  that,  except  in  special  cases,  the  use  of  mixtures  should 
be  avoided  whenever  possible.  The  principal  exception  to  this 
rule  is  in  the  use  of  mixtures  of  methylene  blue  and  methyl  violet 
for  the  tinting  of  the  cheaper  grades  of  paper,  such  as  newsprint; 
but,  even  in  this  case,  the  authors  of  this  Section  consider  it  to 
be  the  best  practice  to  use  the  individual  dyestuffs,  in  order  to 
shade  back  and  forth  in  the  mill,  because  of  the  variation  in 
stocks  during  different  parts  of  the  year. 

38.  Theories  of  Dyeing. — Among  the  various  theories  of  dyeing 
that  have  been  advanced  are  the  mechanical  theory,  the  chemical 
theory,  the  solid  solution  theory,  and  the  adsorption  theory, 
A  full  discussion  of  this  subject  is  not  advisable  in  this  work; 
but,  for  information  concerning  these  theories  or  for  further  infor- 
mation on  the  manufacture  of  intermediates  and  dyestuffs,  the 
reader  is  referred  to  the  various  books  on  dyestuff  manufacture 
and  on  textile  dyeing,  such  as :  Erfurt,  The  Coloring  of  Paper; 
Mathews,  The  Application  of  Dyestuffs,  and  the  literature  of 
dyestuff  manufacturers. 


TESTING  OF  DYESTUFFS 


THE  LABORATORY 


39.  The  Work  of  the  Laboratory. — The  laboratory  work  in 
connection  with  the  testing  of  dyestuffs  should  be  divided  into 
four  general  groups:  first,  a  test  for  strength  and  shade  on  all 


16 


COLORING 


§5 


samples  of  competing  products  submitted  by  manufacturers; 
second,  a  laboratory  check  on  material  received  against  standard 
samples,  to  determine  whether  the  dyestufT  being  tested  is  stand- 
ard in  strength  and  shade;  third,  laboratory  tests  to  be  made  to 
determine  the  composition  of  mixtures  of  dyestuffs  and  the 
chemical  identity  of  individual  dyestuffs  or  mixtures;  fourth,  the 
approximate  matching  of  mill  shades,  as  a  guide  to  subsequent 
matching  in  the  mill. 


Fig.  1. 
Fig.  1  (see  "  Equipment,"  Arts.  40,  41)  shows  the  operating  bench,  on  which  is  mounted  the 
equipment  necessary  for  producing  a  continuous  sheet  of  paper.  Tliis  consists  of  a  motor, 
mounted  on  a  frame  below  the  table  and  driving  directly  the  two  small  beaters  that  are 
shown  on  the  table.  From  the  countershaft  at  the  left  of  the  table,  a  belt  drives  the  small 
pump  that  is  used  for  circulating  and  agitating  the  stock  in  the  stock  chest,  or  for  deliver- 
ing the  stock  into  the  head  box.  The  stock  is  delivered  from  the  head  box  to  the  vat  of 
the  paper  machine.  A  belt  also  drives  the  small  white-water  pump,  whose  delivery  is 
shown  coming  over  the  edge  of  the  head  box,  and  which  is  controlled  by  a  valve.  The 
paper  machine  consists  of  the  vat,  in  which  turns  a  mold  covered  with  wire  cloth,  and 
over  which  travels  the  felt  that  picks  up  the  paper  deposited  on  the  wire.  The  felt  trans- 
fers the  paper  to  the  large  drying  cylinder,  shown  at  the  far  left,  to  which  the  paper  sticks 
and  by  which  it  is  dried  and  given  a  finish.  The  last  belt  from  the  countershaft  drives 
this  dryer  through  a  worm  gear.  The  small  beaters  are  driven  direct  from  the  motor  shaft. 
By  matching  shades  on  a  miniature  machine  of  this  kind,  actual  machine  conditions,  such 
as  return  of  white  water,  drying  temperatures,  etc.,  are  approximated. 


40.  Laboratory  Equipment. — In  addition  to  the  general  equip- 
ment that  the  ordinary  laboratory  has,  consisting  of  chemical 
glass  and  porcelain  ware,  burettes,  graduated  cylinders,  pipettes, 
beakers,  volumetric  flasks,  distilled  water,  hot  plates,  etc.,  the 


§5  DYES  AND  THEIR  PROPERTIES  17 

Ifn^'lf  TT"'"'^  ''  ""''^''^'-y  ^o^-  the  special  work  in  connec 
tion  with  the  testing  of  dyestiiffs- 

canicitf  f  t'""  h"'"'/  '''"  '  P°"^^^  ''  '  P«--l«  dry  stock 
capacitj  ,  the  size  depending  on  the  amount  of  testing  to  be  done 

A  washer  on  such  a  beater  is  of  decided  advantage. 

beaL  Tht"  '"''"'  ''  k'  "''^  ''  '^''^''^  '^'  P"lP  from  the 
cuttW  t^e  Lr'"/'"  ^"  ^«-veniently  and  cheaply  made  by 
cutting  the  bottom  from  an  ordinary  galvanized-iron  pail  and 


smpf  blatt°:^l tld'^ter^'S  orpfner'nl*  At',  '°'  drying  test  sheets.  The 
either  beater,  the  pressure  of  the^oll  nn  fll  k T'  fl"*  ^^^  ^?'"««  °°e  about  8  pounds  In 
simlar  to  that  used  on  Z  regular  mlf  beaters  ^^onH  ""\  ^^  ^^^"^^^^  "^^  aTechanism 

untd  exactly  the  right  shade  is  secured,  as  indicated  hi  onm^"  '"  successive  quantities 
When  the  proper  shade  has  been  obta  ned  the  tfu  n  1  m.^  •'?"  \'*^  *^«  ^est  samples, 
sheet  machine,  and  it  is  then  Hricr?Tr; +1;  Ti"  ■  ^  P  ',^  ""*'^'<^  "^to  sheets  by  means  nf  o 
cylinder  is  fitted  with  a  felt!"and  lith  a  steanTinfet'^and'^f  '^h°""  'V^'  illustration"'  This 
machine  dryer.  As  shown  n  the  illustration  th^f.,^  r  "^"^ •''■''**''"  O"*'*-*-  "ke  a  paper- 
larger  beater  is  used  when  Tlarse  nnmhprTf  1^^"  ''"*'  '"''""'«  a  pressure  gauge      Tho 

t.r'  "  '"°^^^''^°^'^"'  beaS"act"on^rha°nTsTossibYe';!;'h't?''  '''■  -''-' Jtircos.slr; 
beaters   may  also   be  used  as  supplementarv  tn  nf^  »      •  th*",.^"'''""  beater.     These 

machmeis  driven  independentlyTftT^wniecUmotT;.'''"""*  ''°""  ''^  ^'^-   '■     Ea^h 


covering  it  with  a  piece  of  paper-machine  wir 
",stenmg  a  piece  of  paper-machine  wire  to  a 
(3)  Five  gallon  crocks,  with  covers,  for  st 


r    ,      .  -         .  ■;  ^ t-"K^x-xiia,uiiiut;  wire,  or  by  merelv 

fastening  a  piece  of  paper-machine  wire  to  a  wooden  frame 


le. 


oring  moist  pulps. 


18 


COLORING 


§5 


(4)  A  set  of  power-driven  stirrers,  to  stir  the  mixture  of  pulp, 
color,  size,  and  alum.  In  case  the  amount  of  work  of  this  type 
that  needs  be  done  is  limited,  and  the  cost  of  installing  such  a 
set  of  power-driven  stirrers  is  not  warranted,  the  writer  has 
found  several  types  of  egg  beaters  on  the  market  that  are  very 
suitable  for  this  work. 

(5)  A  suction  pulp  mold  or  funnel,  made  from  heavy  sheets  of 
copper,  in  which  paper-machine  wire  is  tightly  stretched.     This 


Fig.  3. 

Fig.  3  .shows  two  of  the  work  benches  in  the  color  laboratory.  On  the  bench  in  the  rear 
are  seen  the  handles  of  a  receptacle  for  keeping  samples  of  beaten  pulp.  Large  quantities 
of  pulp  can  be  weighed  on  the  big  scales,  while  small  amounts  of  dyestuffs,  or  dried  sheets  of 
paper,  can  be  weighed  very  accurately  on  the  delicate  balances  that  are  shown  farther 
down  the  bench.  A  letter  press,  used  for  flattening  sheets,  can  be  seen  at  the  end  of  the 
bench.  On  the  Isench,  in  the  foreground,  arc  the  receptacles  for  the  standard  pulps  required, 
and  the  mixing  cups  for  matching  shades.  It  will  be  noticed  that  the  agitators  in  these  cups 
are  driven  by  a  countershaft,  which  runs  the  length  of  the  bench  and  is  driven  by  a  small 
electric  motor.  Above  the  bench  are  the  jars  and  bottles  containing  the  various  dyestuflf 
solutions,  and  the  rosin,  alum,  starch,  clay,  and  other  materials  that  may  be  required  in 
making  certain  papers.  It  is  necessary  to  approximate,  in  so  far  as  is  possible,  all  con- 
ditions and  factors  of  furnish  and  manufacture. 


wire  should  be  reinforced  with  a  coarser  copper-wire  screen, 
supported  by  a  perforated  copper  plate.  The  neck  of  the  funnel 
should  be  fitted  with  a  rubber  stopper,  so  arranged  that  it  can  be 
mounted  either  in  a  suction  flask  or,  preferabl}^  in  a  large  copper 
receptacle,  fitted  at  the  bottom  with  a  stop  cock,  to  allow  the 
back  waters  to  drain  away  when  the  box  is  not  in  use.     An 


§5 


DYES  AND  THEIR  PROPERTIES 


19 


advantage  in  using  the  suction  flask  is  that  the  color  of  the  back 
waters  can  easil}'  be  seen,  which  permits  an  estimation  of  the 
retention  of  the  dyestuff  by  the  paper.  Suction  may  be  obtained 
by  the  ordinary  water-suction  pump  or  by  means  of  a  small 
vacuum  pump,  connected  to  a  large  intermediate  vacuum 
chamber  in  order  to  secure  a  constant  suction  when  the  mold  is 
in  use. 


Fig.  4. 

Fig.  4  shows  a  recently  developed  sheet  machine.  It  consists  of  a  piece  of  Fourdrinier 
wire,  supported  and  held  fiat  by  a  frame  on  a  leg,  and  so  adjastable  that  it  can  be  made 
level,  and  of  a  box  (tipped  back  in  the  illustration),  which  makes  a  water-tight,  machined 
fit  wnth  the  frame.  A  plug  valve  belo%v  the  frame  (which  forms  a  box)  controls  the  drain- 
age of  the  water  from  the  stock,  which  is  allowed  to  become  quiescent  before  being  drained. 


(6)  Several  thicknesses  of  old  canvass  dryer  felt,  cut  about  16 
inches  square,  to  be  used  with  filter  paper  and  blotting  paper  to 
couch  the  sample. 

(7)  A  dryer,  with  a  revolving  drum  from  1  foot  to  4  feet  in 
diameter,  made  of  copper  or  bronze,  either  steam  or  electrically 
heated,  together  with  a  motor  for  revolving  the  drum,  so  the 
paper  sheets  are  carried  in  between  the  surface  of  the  hot  drum 
and  the  dryer  felt. 

(8)  A  supply  of  one-quart  white-enameled  cups  and  of  wide- 
mouth  glass  bottles. 


20  COLORING  §5 

(9)  A  rough  balance,  sensitive  to  0.01  gram,  for  weighing 
pulps;  this  balance  is  in  addition  to  a  chemical  balance  for 
weighing  to  0.0001  gram. 

41.  Additional  Laboratory  Equipment. — There  is  practically 
no  limit  to  the  additional  expenditures  that  can  be  made  for 
laboratory  equipment.  There  are  miniature  paper  machines  on 
the  market,  ranging  in  size  from  4  inches  to  30  inches  trim,  which 
approximate  the  larger  paper  machines  in  the  majority  of  details. 
Other  pieces  of  experimental  equipment  used  in  laboratories  for 
special  purposes  are  available.  Among  these  may  be  mentioned 
a  tissue-dyeing  machine,  so  arranged  that  the  paper  passes 
through  a  color  box  and  squeeze  rolls,  to  remove  the  excess  of 
color;  and  a  miniature  two-roll,  three-roll,  or  four-roll  calender 
stack,  equipped  with  water  or  color  boxes,  for  making  experi- 
mental runs  on  calender  coloring. 


SEPARATION  OF  DYESTUFFS  INTO  GROUPS 

42.  Identification  of  Coloring  Matters. — The  identification  of 
various  coloring  matters  requires  considerable  experience  and 
patience  in  studying  the  color  reactions  by  which  they  are 
identified.  To  investigate  this  question  thoroughlj^,  requires 
years  of  experience.  However,  since  all  large  dyestuff  manu- 
facturers operate  a  technical  service  department  in  which  men 
who  have  made  this  problem  a  life  study  are  employed  to  handle 
this  work,  the  paper  manufacturer  will  obtain  more  satisfactory 
results  by  depending  on  the  dyestuff  manufacturer  for  informa- 
tion on  any  dyestuffs  he  wishes  to  have  identified. 

Nevertheless,  a  general  knowledge  of  the  separation  of  dye- 
stuffs  into  their  various  groups,  and  of  the  tests  of  behavior 
toward  different  chemicals,  is  important  to  the  paper  manu- 
facturer; it  enables  him  to  generalize  his  information,  and  it 
assists  him  in  making  paper  that  will  meet  special  requirements. 

43.  Separation  of  Aniline  Dyestuffs  and  Pigments. — The 
first  step  is  to  determine  whether  the  coloring  matter  under 
consideration  is  a  soluble  aniline  dj^estuff  or  a  pigment.  The 
pigment  colors  may  be  easih^  identified  as  a  class  by  their  insolu- 
bility in  water,  soluble  Prussian  blue  being  the  exception  to  this 
rule.     The  pigment  colors  used  in  the  paper  industry  being  few 


§5  DYES  AND  THEIR  PROPERTIES  21 

in  number,  and  possessing  certain  characteristics  of  appearance, 
tinctorial  power,  etc.,' are  comparatively  easy  to  identify. 

If  the  coloring  matter  is  soluble  in  water,  the  following  pro- 
cedure should  be  adopted  to  determine:  first,  whether  the  dye- 
stuff  is  a  single  color  or  a  mixture;  second,  to  what  group  it 
belongs;  thu-d,  to  determine,  if  possible,  the  individuality  of  the 
dyestuffs  in  its  particular  group. 

A  small  amount  of  the  dyestuff  is  placed  on  the  point  of  a 
knife  or  spatula,  and  is  gently  blown  onto  a  piece  of  wet  pulp  or 
filter  paper;  this  action  is  called  a  blowout.  If  the  dyestuff 
is  a  mixture,  the  sample  is  separated  into  its  component  parts, 
each  individual  particle  showing  a  spot  of  different  color. 

44.  In  some  cases,  where  the  sample  being  tested  is  a  mixture 
of  two  dj^estuffs  somewhat  similar  in  shade,  it  may  be  difficult 
to  distinguish  the  component  parts  from  a  blowout  on  wet  pulp 
or  filter  paper.  As  a  check  to  the  above  method,  a  small  amount 
of  the  sample  is  placed  on  a  blade  or  spatula  and  blown  onto  the 
surface  of  about  10  c.c.  of  sulphuric  acid,  contained  in  a  small 
porcelain  evaporating  dish.  Different  dyestuffs  give  different 
color  reactions  with  sulphuric  acid,  thus  indicating  at  once 
whether  the  sample  is  an  individual  dyestuff  or  a  mixture. 

45.  Determination  of  Mixtures. — Some  dyestuffs  are  mixtures 
obtained  by  evaporating  to  dryness  solutions  of  two  coloring 
matters  that  have  previously  been  thoroughly  mixed.  Such  a 
mixture  can  be  determined  by  making  successive  dyeings  on 
skeins  of  plain  cotton,  tannin-mordanted  cotton,^  or  wool, 
depending  upon  whether  the  mixture  has  been  determined  to  be 
a  basic,  acid,  or  direct  dyestuff.  If  the  color  is  a  single  dyestuff, 
the  skeins  made  by  a  series  of  dyeings  to  exhaust  the  bath,  will 
show  a  gradual  shading  down  in  strength  of  the  same  shade. 
If  the  dyestuff  is  a  mixture,  then  the  first  and  last  dj^eings  will 
differ  in  shade.  Allowance  must  be  made  for  the  variations  in 
strength  of  the  different  dyeings,  as  such  variations  often 
cause  an  apparent  variation  in  shade. 

'  Tannin-mordanted  cotton  can  be  prepared  by  inserting  boiled-out 
cotton  yarn  into  a  bath  containing  3%  tannic  acid,  based  on  the  weight 
of  the  yarn,  at  140°F.  Raise  the  temperature  of  the  bath  to  200°F.,  and 
hold  for  one  hour.  Steep  until  next  morning,  when  the  yarn  should  be 
wrung  out  and  dried,  but  not  washed.  Dissolve  1%  to  1-J%  tartar  emetic 
in  water,  introduce  the  dried  yarn  at  100°F.,  hold  one-half  hour,  wash,  and 
wring  evenly. 


22  COLORING  §5 

46.  Separation  of  Aniline  Dyestuffs  into  Groups. — The  second 
question  to  determine,  if  the  sample  has  been  shown  to  be  an 
individual  dyestuff,  is  to  what  group  it  belongs.  Only  basic, 
acid  and  direct  dyestuffs,  and  pigment  colors,  are  used  in  the 
paper  industry,  and  tests  for  those  groups  only  will  be  necessary. 
As  previously  stated,  pigment  colors  can  be  identified  by  their 
insolul)ility  in  water,  as  indicated  when  a  blowout  is  made  on 
wet  filter  paper  to  determine  whether  the  color  in  question  is  a 
mixture. 

47.  Method  of  Testing. — Prepare  in  a  test  tube  a  dilute  solu- 
tion of  the  dyestuff;  after  adding  a  few  drops  of  acetic  acid, 
insert  a  thread  of  boiled-out  degreased  wool  and  one  of  tannin- 
mordanted  cotton.  If  the  tannin-mordanted  cotton  is  dyed,  a 
basic  color  is  indicated;  if  the  wool  is  dyed,  an  acid  or  direct  dj'^e 
is  indicated. 

In  a  second  test  tube  containing  a  dilute  solution  of  the  dj'estuff, 
add  a  small  amount  of  Glauber's  salt ;  place  a  cotton  thread  in  the 
test  tube  and  warm  the  solution.  To  determine  whether  the 
thread  was  actuality  dyed  or  mereh-  mechanically  colored,  remove 
the  colored  cotton  thread  and  place  it  in  another  test  tube  that 
contains  distilled  water,  and  boil.  If  the  cotton  retains  its  color, 
the  results  indicate  that  the  sample  being  tested  is  a  direct,  or 
substantive,  dj^estuff. 

If  the  sample  under  examination  colors  both  the  wool  and  the 
tannin-mordanted  cotton,  repeat  the  dyeing  test  in  a  very  dilute 
solution  of  the  dyestuff,  to  which  acetic  acid  has  been  added.  If 
the  sample  is  an  acid  dyestuff,  it  will  color  the  wool;  but,  if  it  is 
basic,  it  will  stain  only  the  tannin-mordanted  cotton.  To  sub- 
stantiate the  basic  character  of  the  dyestuff  in  the  latter  case,  add 
some  tannic  acid  to  a  separate  fresh  solution  of  the  dyestuff,  to 
which  has  been  added  some  sodium  acetate;  if  the  sample  is  a 
basic  dye,  a  precipitate  of  tannin  lake  will  occur. 

48.  Subsequent  Steps. — The  subsequent  determination  of  the 
individuality  of  the  sample  submitted  is  a  process  of  analytical 
character  that  requires  a  long  training.  To  become  efficient  in 
these  methods  of  determination,  which  are  based  upon  the 
reactions  of  the  different  dyestuffs  with  weak  and  strong  alkalis, 
weak  and  strong  acids,  reduction,  and  oxidation,  would  require 
more  time  and  labor  than  the  paper  manufacturer  or  the  paper- 
mill  chemist  could  devote  to  it.     As  stated  before,  the  dyestuff 


§5  DYES  AND  THEIR  PROPERTIES  23 

manufacturers  have  men  trained  to  do  this  work;  and,  in  all  cases 
where  the  actual  identification  of  the  sample  is  required,  the 
sample  should  be  submitted  to  the  technical  laboratories  of  the 
dvestuff  manufacturers. 


OTHER  TESTS 

49.  Testing  for  Strength  and  Shade. — The  testing  of  a  given 
dyestuff  for  strength  and  shade  is  more  important  than  its 
identification,  because  such  tests  show  the  actual  money  value  of 
the  dyestuff  to  the  consumer.  All  work  in  the  laboratory  should 
be  done  on  the  same  stock  as  that  to  be  used  on  the  run  of  paper 
for  which  the  particular  formula  is  being  worked  out.  The 
number  of  pulps  kept  on  hand  in  the  laborator}^  depends  on  the 
grades  of  paper  made  in  the  particular  mill.  A  laborator}^  doing 
work  for  a  mill  making  numerous  grades  of  paper  should  carry  the 
following  pulps  in  stock:  unbleached  sulphite  (quick  cook), 
unbleached  sulphite  (Mitscherlich),  bleached  sulphite,  kraft, 
soda,  groundwood,  cotton  linters,  and  rag  stock. 

50.  Preparation  of  Stocks. — These  stocks  are  prepared  for 
laboratory  use  by  one  of  two  methods.  If  the  stock  is  to  be 
prepared  in  the  laboratory,  it  is  placed  in  the  miniature  beater, 
where  it  is  beaten  until  it  gives  the  proper  feel  or  freeness  test  (see 
Sections  on  Refining  and  Testing  of  Pulp,  Vol.  Ill,  and  Beating 
and  Refining,  Vol.  IV).  The  excess  of  water  is  then  removed  by 
means  of  a  suction  funnel  or  a' laboratory  pulp  thickener.  The 
pulp  is  next  placed  in  a  crock,  and  it  is  kneaded  until  the  moisture 
present  is  evenly  distributed;  the  crock  must  be  kept  tightly 
covered  at  all  times.  In  some  cases,  it  is  easier  to  take  the  stock 
directh'  from  the  beater  room,  before  the  size  and  alum  have  been 
added  to  the  mill  beaters;  and,  after  removing  the  excess  of  water, 
the  same  procedure  is  followed  as  with  the  laboratory-beaten 
pulp. 

51.  Moisture  Determination. — Moisture  determinations  should 
then  be  made,  to  ascertain  the  weight  of  wet  pulp  that  will 
be  necessary  to  make  a  hand  sheet  of  a  required  air-dr}- 
weight.  These  moisture  tests  are  in  constant  use,  and  the 
moisture  content  should  be  accurately  determined  at  frequent 
intervals.  The  basis  weight  for  pulp  to  be  used  for  hand  samples 
varies  in  different  mills,  but  an  average  of  2^  grams  of  air-dry 
pulp  will  make  a  6-inch  diameter  hand  sheet  of  average  thickness. 


24  COLORING  §5 

The  moisture  content  of  the  prepared  pulps  should  be  of  such  a 
consistency  that  from  10  to  15  grams  of  the  wet  pulp  will  be  equi- 
valent to  2|  grams  of  the  dried  pulp.  Certain  pulps,  such  as 
jute,  manila,  kraft,  groundwood,  and  old  newsprint,  are  readily 
attacked  by  mold  and  bacteria.  When  fermentation  or  bacterial 
change  occurs,  as  indicated  by  the  color  or  odor  of  the  pulp,  it  is 
advisable  to  prepare  a  new  supply. 

52.  Approximate  Methods. — For  straight  color  evaluation  work, 
either  unbleached  sulphite  or  mixtures  of  equal  parts  of  unbleached 
sulphite,  soda,  and  groundwood  are  used;  which  to  use  depends, 
of  course,  on  the  grades  of  paper  made  at  that  particular  mill. 

The  dyestuff  to  be  tested  should  be  made  up  into  a  standard 
solution,  by  weighing  out  on  an  accurate  balance,  dissolving  in 
hot  water  in  a  casserole,  and,  after  solution  is  complete,  pouring 
into  a  volumetric  flask  and  making  up  to  the  proper  volume.  A 
convenient  strength  for  these  solutions  is  0.5  gram  of  dyestuff  per 
liter. 

53.  For  matching  a  product  sample  of  dyestuff  against  a  stand- 
ard sample,  to  determine  the  strength  and  shade,  the  following 
approximate  methods  are  suggested: 

(a)  Before  the  solutions  are  made  up  to  the  required  volume, 
spot  each  of  the  solutions  side  by  side  on  a  filter  paper.  Note  the 
difference  in  strength,  and  increase  the  volume  of  one  of  the 
stronger  dye  solutions  {i.e.,  dilute  it)  to  the  point  where  further 
tests  show  the  solution  to  be  of  equal  strength  with  one  of  the 
weaker  ones.  By  comparing  the  volumes  of  the  two  solutions, 
an  approximation  to  their  relative  strengths  can  be  made,  which 
will  save  the  time  required  for  determining  the  actual  strength 
test  by  making  hand  samples. 

(b)  Another  approximate  method,  known  as  the  dip  test,  is 
made  by  cutting  a  piece  of  heavy  filter  paper  in  such  a  manner 
that  it  will  have  two  equal  legs  or  forks.  The  standard  solution 
and  that  to  be  tested  are  then  placed  side  by  side,  one  leg  of  the 
filter  paper  being  dipped  into  each  of  the  two  solutions.  Upon 
examining  the  filter  paper  after  drying,  an  approximation  to  the 
relative  strengths  can  be  obtained. 

54.  Standard  Solutions. — In  addition  to  the  color  solutions, 
which  should  l)e  made  up  fresh  as  required,  the  following  stand- 
ard solutions  should  be  kept  on  hand  at  all  times;  namely,  size, 
alum,  soda  ash,  and  clay.     For  laboratory  work,  a  convenient 


§5  DYES  AND  THEIR  PROPERTIES  25 

strength  of  the  solutions  of  the  first  three  items  is  2|%;  the 
suspension  of  clay  should  be  approximately  20  parts  of  water  to  1 
part  of  clay,  and  the  bottle  containing  it  should  be  thoroughly 
shaken  each  time  before  using.  The  following  description  gives 
the  methods  and  relative  proportions  used  very  successfully  in  one 
laboratory,  and  they  can  be  used  as  a  guide  for  other  laboratories : 

55.  On  a  rough  balance,  weigh  out  the  samples  of  wet  pulp, 
equivalent  to  2.5  grams  air-dry  weight,  and  place  in  a  porcelain- 
lined  cup.  Add  50  to  100  c.c.  of  water,  and  mix  the  stock  for  5 
minutes  by  means  of  the  mechanical  stirrers  or  paddles  mentioned 
in  Art.  40.  At  five-minute  intervals,  add  the  color  solution,  size, 
and  alum;  if  fillers  be  used,  they  should  be  added  at  a  five-minute 
interval  before  the  size.  After  all  material  has  been  added  to  the 
cup,  and  the  total  stirring  time  is  equal  to  39  minutes,  add 
approximatel}^  500  c.c.  of  water,  stirring  continuously  for  a 
minute  or  more. 

56.  Making  Hand  Samples.— The  diluted  pulp  is  now  poured 
into  the  funnel  or  mold,  and  the  suction  is  applied.  If  a  suction 
flask  be  used,  it  is  rotated,  finally,  at  an  angle  that  will  completely 
remove  the  water  that  tends  to  adhere  to  certain  portions  of  the 
sheet  of  pulp.  The  suction  is  then  turned  off,  and  the  sheet  is 
carefully  loosened  on  one  side  by  means  of  a  spatula.  The  sheet 
is  then  lifted  from  the  wire  and  placed  between  two  sheets  of 
filter  or  white  blotting  paper.  If  an  ordinary  rolling  pin  be  used 
to  couch  the  sample,  the  sample  sheet  and  blotting  (or  filter) 
papers  should  be  placed  between  pieces  of  ordinary  dryer  canvass. 
If  a  wringer  is  to  be  used,  the  amount  of  blotting  or  filter  paper 
should  be  doubled,  as  the  sample,  covered  by  this  paper,  is 
passed  through  the  wringer.  The  remaining  moisture  should 
be  removed  on  drying  on  the  rotary  drum  dryer  (Art.  40)  or  on  a 
hot-plate.  When  drying  these  hand  samples  on  a  drum  dryer,  the 
sheet  should  be  reversed  after  every  revolution  of  the  drum,  to 
hasten  the  drying  and  to  avoid  the  danger  of  burning  the  color 
to  the  surface. 

57.  Color  Formulas. — All  color  formulas  should  be  given  in 
terms  of  1000  pounds  of  stock.  When  the  above-mentioned 
proportions  of  2.5  grams  of  air-dry  pulp,  a  color  solution  of  0.5 
gram  per  liter,  and  2.5%  solutions  of  size  and  alum  are  used,  every 
5  c.c.  of  color  solution  is  equivalent  to  1  pound  of  dyestuff  per  1000 
pounds  of  stock;  and  1  c.c.  of  size  or  alum  is  equivalent^to_[10 


2G  COLORING  §5 

pounds  of  that  material  per  1000  pounds  of  stock.  ^  When  testing 
individual  dyestuffs  against  a  given  standard  for  strength  and 
shade,  a  0.2%  dyeing  is  recommended  for  basic  dyestuffs,  and  a 
0.4%  dyeing  for  acid  and  direct  colors;  i.e.  add  10  c.c.  and  20  c.c. 
of  dycstuff,  respectively,  to  the  pulp. 

58.  Strength  of  Yellow  Dyestuffs. — For  determining  the 
strength  of  yellow  dyestuffs,  small  standard  amounts  of  either 
methylene  blue  or  of  safranine  are  added  to  the  stock  of  both 
the  standard  and  the  product  sample  dyeings.  A  greenish 
tint  is  produced,  which  registers  more  distinctly  than  yellow  on 
the  eye.  The  strength  of  the  yellow  dycstuff  is  then  determined 
by  the  degree  of  shading  toward  the  true  shade  of  either  the 
methylene  blue  or  the  safranine. 


FASTNESS  TESTS 

59.  Varieties  of  Fastness. — For  every  grade  of  paper,  those 
dyestuffs  should  be  selected  which  will  give  the  most  economical 
match,  consistent  with  the  quality  to  be  maintained.  In  certain 
papers,  fastness  to  (resistance  to  change  by)  light  is  the  impor- 
tant qualit}';  while  in  others,  fastness  to  alum,  acid,  or  alkali  may 
be  the  properties  required.  Fortunately,  the  paper  industry 
does  not  have  as  many  fastness  tests  to  which  the  dyestuffs  must 
be  subjected  as  will  be  found  in  the  textile  industries.  With  a 
few  exceptions,  fastness  to  light,  acid,  alkali,  heat,  and  chlorine 
are  the  only  tests  necessarj^  in  the  selection  of  dyestuffs  for  paper. 

60.  Fastness  to  Light. — The  first  important  fact  to  consider 

in   making  a  test  for  fastness  to  light  is  that  all  stocks  are 

discolored  in  the  sunlight  with  varying  degrees  of  rapidity;  and 

any  discoloration  that  may  be  due  to  exposure  should  be  followed 

through,  to  determine  whether  the  change  in  color  is  due  to  the 

pulp,  to  the  dyestuffs,  or  to,  perhaps,  a  combination  of  both. 

Bonds,  ledger,  cover  papers,  and  wall  papers  are  grades  where 

fastness  to  light  is  important.     These  papers  are  exposed,  in  the 

course  of  their  use,  to  varying  degrees  of  sunlight,  and  a  dycstuff 

should  be  selected  whose  fastness  to  light  approaches  as  nearly  as 

is  possible  to  the  fastness  of  the  pulps  from  which  the  paper  is 

made.     In  newsprint,  wrapping  papers,  and  cheap  grades  of  book 

'  0.5  g.  dye  stuff  per  liter  (practically  =  1000  g.)  =  0.0005  g.  per  c.c. 
5  c.c.  =  .0025  g.  and  .0025  fg.  dye  per  2.5  g.  pulp  =  1  g.  to  1000  g.  or 
1  lb.  to  1000  lb.  1  c.c.  alum,  etc.  =  .025  g.  per  2.5  g.  pulp  =  10  g.  per 
1000  g.  or  10  lb.  alum,  etc.  per  1000  lb.  pulp. 


§5  DYES  AND  THEIR  PROPERTIES  27 

and  magazine  papers,  there  is  never  any  need  to  sacrifice  cheap- 
ness for  fastness  properties.  Consequently,  in  all  papers  where 
groundwood  (which  discolors  rapidly  in  sunlight  and  is  naturally 
dull  in  appearance)  is  used,  basic  colors  should  be  adopted, 
because  of  their  low  cost  and  extreme  brilliance. 

No  paper  can  be  colored  with  organic  dyes  so  it  will  be 
absolutely  fast  to  sunlight.  Certain  pigments,  chief  of  which  are 
those  derived  from  the  vat  colors,  possess  the  greatest  fastness, 
while  the  acid,  direct,  and  basic  dyestuffs  follow  in  this  order. 

61.  Tests  for  Fastness  to  Light. — There  are  several  ways  in 
which  fastness-to-light  tests  can  be  made.  Exposure  to  direct 
sunlight  is  the  most  conclusive  test,  but  it  is  difficult  to  obtain 
definite  comparative  results  bj^  this  method,  because  of  the 
varying  degree  of  brightness  of  sunlight  at  various  times  of  the 
day  or  year.  Laboratory  tests  may  also  be  made  means  of  a 
fadeometer  or  an  ultra-violet  lamp.  When  comparisons  are  to  be 
made  between  two  different  dyestuffs  or  between  two  different 
stocks  using  the  same  dj^estuff,  the  several  dyeings  should  be 
exposed  to  the  raj^s  of  these  lamps  at  the  same  time;  because, 
even  in  the  laboratory,  the  conditions  affecting  the  heat  and 
strength  of  the  rays  emitted  by  the  lamps  vary  to  a  certain  extent. 

For  reasons  just  explained,  no  numerical  values  as  to  the 
comparative  fastness  of  all  dj^estuffs  is  possible.  All  comparisons 
must  be  relative;  for  which  reason,  it  is  recommended  that 
dj'estuffs  be  divided  into  five  general  groups,  when  making  such  . 
tests,  rather  than  to  try  to  classify  them  in  a  numerical  order 
based  on  percentages. 

62.  Fastness  to  Alkali. — Fastness  to  alkali  is  important  in  such 
papers  as  soap  wrappers,  wall  papers,  and  box  cover  papers, 
where  alkaline  pastes  are  used,  or  for  any  type  of  wrapping 
papers  that  are  liable  to  come  into  contact  with  alkaline  materials. 
A  spot  test,  with  |%  solution  of  caustic  soda  or  2%  solution  of 
soda  ash,  is  sufficient  for  commercial  purposes.  Fastness  to 
alkali  is  also  necessary'  in  ledger  and  bond  papers,  so  they  shall 
be  fast  to  chemical  erasures.  For  testing  the  fastness  against 
chemical  erasure,  laboratory  samples  of  the  paper,  made  with  the 
dyestuff  material  being  examined,  should  be  spot-tested. 

63.  Fastness  to  Acids. — For  dyestuff  tests  on  fastness  to  acids, 
colors  may  be  divided  into  three  groups :  The  first  group  includes 
those  dyestuffs  which  are  unaffected  by  alum  or  a  1  %  solution  of 


28  COLORING  §5 

sulphuric  acid;  the  second  group  includes  those  which  are  affected 
by  alum  and  sulphuric  acid;  the  third  group  includes  those  dye- 
stuffs  which  are  affected  by  a  1  %  solution  of  sulphuric  acid,  but 
are  not  altered  by  alum. 

All  direct  dyestuffs  are  affected  in  shade  by  the  use  of  alum 
and  by  spot  tests  of  sulphuric  acid,  being  dulled  to  a  considerable 
extent.  Acid  colors  as  a  class  are  fast  to  acids,  one  important 
exception  being  metanil  yellow,  which  is  very  sensitive  to  even  a 
slight  excess  of  alum.  Basic  dj-estuffs  as  a  class  are  not  affected 
by  alum;  but  no  general  rule  applies  as  to  their  reactions  with 
sulphuric  acid. 

64.  Fastness  to  Heat. — No  special  laboratory  tests  are  possible 
that  will  determine  the  effect  of  heat  on  finished  paper,  for 
finished  paper  is  never  subjected  to  heat  above  a  temperature 
harmful  to  the  dyestuff.  Nevertheless,  the  effect  of  heat  on 
various  dyestuffs  during  the  process  of  paper  manufacture  is  an 
important  consideration,  and  a  practical  knowledge  of  which  dye- 
stuffs  are  thus  affected  is  essential.  When  the  dryers  are  some- 
what too  hot,  certain  acid  dyestuffs  seem  to  be  drawn  to  the 
surface  of  the  paper,  giving  a  decidedly  spott}^  appearance  to  the 
sheet  and  a  difference  in  the  color  of  the  two  sides  {tivo-sidedness). 
The  uniformity  of  color  throughout  the  run  may  be  seriously 
affected  by  variation  of  temperature  of  the  dryers.  Metanil 
yellow  behaves  worst  in  this  respect,  especially  in  the  presence  of  a 
slight  excess  of  alum.  Certain  basic  and  direct  dyestuffs  give  a 
different  shade  to  the  paper  when  it  first  comes  off  the  machine 
from  that  which  prevails  when  the  sheet  is  cooled.  When  such 
dyestuffs  are  used,  allowance  for  this  effect  must  be  made  when 
matching. 

65.  Fastness  to  Chlorine. — In  paper  manufacture,  trouble 
with  chlorine  is  experienced  where  freshly  bleached  stock  is 
furnished  to  the  beater.  In  cases  where  the  stock  is  so  poorly 
washed  that  large  excesses  of  chlorine  still  remain,  an  antichlor, 
such  as  sodium  sulphite  or  sodium  thiosulphate,  should  be  added 
to  the  stock  in  the  beater,  to  react  with  the  free  chlorine.  To 
determine  the  effect  of  poorly  washed  stock  upon  certain  dye- 
stuffs,  two  hand  samples  should  be  run  in  the  laboratory,  to  one 
of  which  should  be  added  a  dilute  solution  of  bleaching  powder. 
It  should  be  remembered  that  the  use  of  antichlor  usually 
leaves  the  stock  acid. 


§5  DYES  AND  THEIR  PROPERTIES  29 

66.  Tests  Should  Be  Comparable.— The  above-described  tests 
should  be  made  as  compai'able  to  the  actual  working  conditions 
in  the  mill  as  is  possible.  Where  time  permits,  the  dyestuff 
manufacturer  will  give  information  as  to  the  reactions  of  the 
dyestuff  with  various  chemicals.  In  other  cases,  special  tests 
should  be  made  by  the  above  methods,  using  actual  mill  stocks 
and  mill  solutions,  in  order  to  get  the  best  practical  results. 

67.  Effect  of  Fillers. — All  fillers  used  in  the  process  of  paper 
manufacture  have  a  certain  absorptive  power  for  dyestuffs,  the 
degree  of  absorption  depending  on  the  nature  of  the  filler  and  also 
on  the  relative  affinity  of  the  dyestuffs  for  the  pulps  and  fillers. 
When  the  fillers  are  added  to  the  beater  in  the  presence  of  dye- 
stuffs,  a  state  of  equilibrium  is  established  between  the  amount 
of  dyestuff  absorbed  by  the  fillers  and  that  retained  by  the  pulp. 
Since  some  of  the  filler  is  lost  in  the  backwaters,  there  is  a  cor- 
responding loss  in  available  dyestuff.  Concrete  information 
concerning  relative  absorptive  powers  of  various  fillers  for  indi- 
vidual dyestuffs  would  benefit  the  paper  maker.  Research  work 
on  this  subject  has  been  started,  and  the  results  obtained  will  be 
submitted  to  the  paper  industry  as  a  Report  of  the  Committee 
on  Dvestuffs. 


MATCHING  TESTS 

68.  Matching  Shades. — Matching  shades  in  the  laboratory, 
together  with  subsequent  work  in  the  mill,  is  dependent  on  the 
character  of  the  stocks,  chemical  furnish,  finish  and  the  class  of 
dyestuff  to  be  used,  as  well  as  on  the  training  of  the  eye  to  detect 
readily  slight  differences  in  strength  and  shade.  The  pulp  and 
chemical  furnish  is  usually  given  to  the  laboratory  for  the 
sample  of  paper  to  be  matched.  If  not,  a  microscopic  analysis 
will  determine  the  percentage  of  various  pulps  in  the  furnish; 
and  approximate  tests  for  sizing  and  loading  will  determine  the 
proportions  of  size,  alum,  and  fillers  necessary.  If  the  paper 
sample  to  be  matched  be  heavily  calendered,  it  should  be  steamed 
for  a  few  minutes,  to  graduate  the  finish  to  approximately  that 
of  the  laboratory  hand  samples,  so  the  true  color  of  the  paper 
sample  can  be  noted.  If  the  sheet  be  water  finished,  allowance 
must  be  made  for  the  darkening  of  the  sheet  by  this  treatment. 
In  matching  samples  of  glassine  paper,  satisfactory  results  can 
be  obtained  only  when  the  highly  hydrated  pulp  used  in  the 


30  COLORING  §5 

manufacture  of  this  type  of  paper  is  obtained  from  the  mill 
beater;  for  it  is  impossible  to  hydrate  stock  to  that  degree  in  a 
miniature  beater.  For  a  given  shade,  approximately  one-half  the 
amount  of  dyestuff  is  required  for  glassine  papers  that  is  necessary 
for  the  ordinary  drj'-finished  sheets. 

69.  When  matching  am^  new  shades,  it  is  advisable  to  do  the 
work  by  daylight,  a  north  light  being  preferable  to  any  other  for 
this  purpose.  The  various  daylight  lamps  on  the  market  are 
valuable  for  matching  shades  when  such  work  cannot  be  done 
in  the  daytime;  but  the  change  of  shade  of  different  dyestuffs 
under  artificial  light  will  not  hold  constant  under  any  daylight 
lamp  at  present  available. 

The  general  method  for  preparing  hand  samples  from  various 
stocks  and  with  various  chemicals  has  been  previously  discussed. 
When  matching  shades  in  the  laboratory,  the  same  methods 
apply  as  when  testing  for  strength  and  shade  of  an  individual 
dyestuff,  except  that  a  combination  of  colors  is  used  to  match 
the  given  sample. 

70.  Matching  Dyestuffs. — To  save  time  in  making  laboratory 
matches,  the  following  procedure  should  be  adhered  to  in  order 
to  approximate  the  quantity  of  dyestuffs  required  to  obtain  a 
given  shade.  After  the  dj^estuff,  size,  and  alum  have  been  added 
to  the  stock  in  a  porcelain-lined  cup,  a  small  amount  of  the  stock 
should  be  taken  from  the  cup,  squeezed  between  the  thumb  and 
forefinger,  and  placed  on  a  hot-plate  to  dry.  On  comparison 
with  the  given  sample,  an  approximation  can  be  made.  A 
small  test  sample  of  this  kind  should  be  taken  out  following  the 
addition  of  each  new  furnishing  of  dyestuff;  for,  in  this  way,  a 
close  approximation  can  be  reached  with  one  weighing  of  stock, 
and  time  is  saved  in  making  finished  hand  samples.  When 
matching  a  shade  where  the  quantities  of  each  dyestuff  are  being 
varied  slightly,  care  should  be  taken  not  only  to  measure  out  the 
dyestuff  accurately  but  also  to  watch  carefully  the  order  of  the 
addition  of  color,  size,  and  alum  and  the  length  of  time  of 
stirring. 

71.  Amount  of  Dyestuff  to  Use. — By  using  the  methods 
described  in  the  last  article,  the  quantity  of  dyestuff  necessary 
per  1000  pounds  of  stock  can  easily  be  calculated.  Experience 
has  shown  that,  as  a  rule,  the  amount  of  dj^estuff  required  to 
match  a  sample  in  the  laboratory  is  usually  in  excess  of  that 


§5        PRACTICAL  APPLICATION  OF  DYESTUFFS        31 

actually  required  in  the  mill.  For  this  reason,  it  is  recommended 
that,  in  all  cases  where  a  laboratory  formula  is  to  be  used  in  the 
mill,  the  first  addition  of  dyestuff  to  the  beater  should  be  only 
75%  of  that  called  for  by  the  laboratory  formula. 

72.  Cost  Comparisons. — The  determination  of  the  actual 
color  value  of  a  dyestuff  is  not  always  a  simple  problem.  This  is 
due  to  three  facts:  first,  it  is  very  easy  to  reduce  a  particular 
dyestuff  5%  or  10%,  in  order  to  meet  price  competition;  but  this 
reduction  may  not  be  observed  by  the  paper  manufacturer,  due 
to  variations  in  pulps  or  in  mill  conditions.  Second,  in  certain 
grades  of  paper,  it  is  difficult  to  estimate  the  depth  of  a  shade 
within  an  accuracy  of  10%;  this  is  particularly  true  in  the  case  of 
yellow  shades  on  all  papers,  and  to  all  shades  on  the  cheaper 
grades  of  wrapping  papers  and  boxboards.  Third,  while  it  is 
comparatively  simple  to  compare  two  dyestuffs  of  the  same 
constitution,  such  as  two  methyl  violets  or  two  methylene  blues, 
it  is  difficult  for  the  manufacturer  to  obtain  the  actual  color 
value  when  deciding  between  a  low-cost  dye  of  comparatively 
poor  fastness  qualities  and  a  higher-price  dye  of  superior  qualities. 
This  problem  resolves  itself  into  a  broad  study  of  what  the  con- 
sumer of  the  paper  actually  wants,  and  to  conditions  of  eflftciency 
in  the  manipulation  of  dyestuffs  throughout  the  process  of 
manufacture.  It  is  worth  while,  however,  to  make  a  laboratory 
comparison  of  dyestuffs,  and,  from  the  percentages  required  to 
give  matched  samples,  to  calculate  from  the  price  of  the  dyestuffs, 
the  money  value  of  each  in  the  paper. 


PRACTICAL  APPLICATION  OF  DYESTUFFS 


COLOR  AND  BEATER  ROOMS 

73.  Methods  of  Coloring. — The  methods  employed  in  the 
coloring  of  paper  may  be  divided  into  several  classes;  namely, 
beater  coloring,  calender  coloring,  combination  of  beater  and 
calender  coloring,  tub  coloring,  dipping,  specialty  coloring  by 
special  processes,  and  coloring  of  coated  papers.  Approximately 
95%  of  the  coloring  of  paper  is  done  in  the  beater;  for  which 
reason,  the  greater  part  of  the  remainder  of  this  Section  will  be 
devoted  to  that  branch. 


32  COLORING  §5 

74.  Color  Room  Essential. — A  well-equipped  color  room  is 
essential,  regardless  of  the  process  by  which  the  paper  is  colored. 
While  slight  variations  in  equipment  are  necessary  in  mills 
doing  other  than  beater  coloring,  such  variations  must  depend 
on  mill  conditions,  and  they  will  not  be  discussed  in  detail  at  this 
point. 

Every  beater  room  should  have  an  adjoining  color  room,  to  be 
used  for  the  storage  of  all  kegs  and  barrels,  and  for  the  weighing 
and  dissolving  of  all  dyestuffs.  This  color  room  should  have  a 
cement  floor  with  two  drains;  one  drain  approximately  in  the 
center  of  the  room,  the  other  beneath  the  outlet  of  a  hot-water 
storage  tank.  Shelves  should  be  built  along  one  side  of  the 
room,  for  the  storage  of  tins  and  small  containers,  and  the  room 
should  have  a  wall  table,  on  which  the  balances  are  placed. 

75.  Equipment  of  Color  Room. — A  well-equipped  color  room 
should  contain  one  rough  balance,  having  a  capacity  of  20  pounds, 
weighing  to  ounces,  and  a  finer  balance,  having  a  range  from  ^j 
ounce  to  2  pounds.  The  accuracy  of  these  balances  should  be 
tested  at  regular  intervals.  The  authors  recommend  the  ordi- 
nary type  of  computing  grocery  scale,  with  a  glass  top,  as  best 
suited  to  this  work. 

76.  Hot-Water  Storage  Tank. — A  hot-water  storage  tank, 
having  a  capacity  of  from  50  to  100  gallons,  capable  of  furnishing 
a  constant  supply  of  hot  water  at  a  temperature  just  below 
boiling,  should  be  available.  The  best  type  is  equipped  with  a 
thermostatic  control,  which  is  connected  to  a  steam  pipe  in  such 
a  manner  that,  when  the  temperature  falls  below  200°F.,  steam 
will  automatically  be  injected  into  the  tank  until  the  temperature 
is  raised  to  the  desired  point,  when  the  steam  is  shut  off. 

77.  Barrels  and  Other  Containers. — In  most  cases,  the  barrels 
and  larger  containers  are  left  standing  on  the  floor  of  the  color 
room.  To  insure  that  the  dyestuffs  are  kept  dry,  it  is  recom- 
mended that  a  platform  be  built  2  or  3  inches  above  the  floor, 
on  which  to  place  the  barrels.  A  still  better  plan  is  to  arrange 
bins,  similar  to  flour  bins,  into  which  the  ordinary  size  barrel 
will  fit;  such  an  arrangement  insures  a  dust-proof  storage  space 
in  the  color  room  for  dyestuffs.  If  the  barrels  or  kegs  of  dyestuffs 
are  left  open  on  the  floor,  the  names  of  the  dyestuffs  should  be 
stenciled  on  their  sides.  It  has  been  the  practice  of  dyestuffs 
manufacturers  to  label  their  containers  on  the  covers.     Upon 


§5        PRACTICAL  APPLICATION  OF  DYESTUFFS        33 

removing  the  covers  in  the  color  room,  they  often  become  mis- 
placed by  being  set  on  the  wrong  barrels.  In  their  powdered 
form,  many  aniline  dyestuffs  have  a  similar  appearance  under 
artificial  light;  hence,  unless  the  barrels  are  thoroughly  marked 
on  the  sides,  mistakes  are  liable  to  occur  that  may  prove  serious. 
Copper-lined  containers,  ranging  in  capacity  from  10  to  25 
gallons,  are  the  best  for  dissolving  dyestuffs;  but  galvanized-iron 
pails  and  wooden  half-barrels  are  used  extensively^  for  this 
purpose.  Wooden  containers,  however,  have  the  disadvantage 
of  soaking  up  a  limited  amount  of  the  dyestuff  when  first  used, 
and  they  are  more  difficult  to  clean.  Plain  iron  containers  must 
never  be  used.  LTpon  emptying  the  containers,  they  should  be 
thoroughh'  cleaned,  turned  upside  down  to  dry,  and  thus  left  in 
condition  for  further  use. 

78.  Dissolving  Dyestuffs. — The  following  is  the  proper  method 
for  dissolving  dyestuffs:  Fill  the  container  with  hot  water  from 
the  storage  tank;  sprinkle  in  the  dyestuff  very  slowly  with  one 
hand  while  stirring  with  the  other,  the  stirring  being  continued 
until  all  the  dyestuff  is  dissolved.  After  the  solution  is  complete, 
cold  water  should  be  added  as  a  safeguard,  to  prevent  the  forma- 
tion of  granite  fibers  on  mixed  furnishes,  which  often  occurs  when 
the  dyestuff  solution  is  added  to  the  beater  in  a  too-hot  condition. 
The  quantity  of  water  required  depends  upon  the  individual 
dyestuff.  The  best  general  rule  to  follow  is  to  use  a  minimum  of 
40  parts  of  water  to  each  one  part  of  basic  dyestuff.  The  solu- 
bility of  some  basic  dyestuffs  is  increased  by  the  use  of  acetic 
acid,  in  which  case,  the  best  results  are  obtained  bj'  mixing  an 
equal  weight  of  the  acid  with  the  basic  dyestuff  and  adding  the 
hot  water  to  the  mixture,  with  constant  stirring.  Hard  water 
has  the  property  of  precipitating  all  basic  dyestuffs  and  certain 
direct  dyestuffs.  Whenever  it  is  necessary  to  use  hard  water  for 
dissolving  dyestuffs,  a  small  amount  of  acetic  acid  should  be 
added  to  the  dissolving  water,  to  compensate  for  the  temporary 
hardness. 

79.  Solution  Storage  Tanks. — In  mills  where  a  single  grade 
of  paper  is  run  continuously,  such  as  newsprint,  it  is  advantageous 
to  have  large  mixing  and  storage  tanks  for  the  dj^estuff  solutions. 
The  best  type  for  this  purpose  is  a  cj-lindrical  wooden  tank  con- 
taining a  paddle  agitator,  the  size  depending  on  the  production 
of  the  mill.     When  storage  tanks  are  used,  solutions  of  basic 


34  COLORING  §5 

dyestuffs  should  never  be  made  up  more  than  24  hours  in 
advance;  for,  after  a  period  of  time,  the  strength  of  the  dyestuff 
increases.  However,  acid  and  direct  dyestuffs  can  be  stored  in 
such  tanks  for  several  daj'^s. 

80.  Beater-Room  Equipment. — In  addition  to  that  previouslj^ 
mentioned,  the  equipment  necessary  for  efficient  beater  coloring 
includes  a  small  truck,  hand  mold,  hot  plate,  sieve,  or  strainer, 
and  various  volumetric  measures,  such  as  pint,  quart,  and  two- 
quart  dippers. 

The  container  that  is  used  for  dissolving  the  dyestuff  can  be 
kept  on  the  truck,  for  conveying  the  color  from  the  color  room 
to  the  different  beaters.  A  small  hand  mold,  from  2  to  3  inches 
in  diameter,  is  used  to  make  hand  samples  of  the  stock  from  the 
beaters  while  the  initial  formula  is  being  built  up.  If  a  hot-plate 
(electric  or  steam)  be  used  to  dry  out  such  samples,  the  time  that 
would  otherwise  be  lost  in  running  back  and  forth  to  and  from 
the  machine  room  to  dry  the  samples  on  the  paper  machine  is 
saved;  also,  in  some  cases,  such  as  starting  up  Monday  morning, 
the  dryers  may  not  be  hot  enough  to  dry  the  samples  satis- 
factorily, and  further  time  is  lost.  The  initial  small  cost  of  the 
hot-plate  will  be  more  than  compensated  for  b}^  the  satisfactory 
service  obtained  from  it. 


DETAILS  OF  COLORING  PROCESS 


ACTION  OF  DYESTUFFS 

81.  Why  Shades  Vary.— The  shade  produced  by  a  dyestuff 
on  different  stocks  varies  between  wide  limits.  With  basic 
colors,  stock  containing  a  certain  percentage  of  tannin-like  or 
lignaceous  material  will  be  colored  a  much  deeper  and  duller 
shade  than  stocks  that  have  been  partly  or  wholly  bleached, 
since  the  bleaching  process  removes  this  material.  For  example, 
stocks  such  as  unbleached  wood  pulps,  jute,  etc.  contain  sufficient 
lignaceous  material  to  combine  with  all  the  dyestuff,  leaving  the 
back  waters  perfectly  clear.  Likewise,  pulps  obtained  from 
different  cooks  in  the  same  mill  will  often  vary  between  25% 
limits  in  the  amount  of  dyestuff  required  to  produce  a  given 
shade.  In  other  words,  a  very  hard  or  raw  cook  requires  less  dj-e- 
stuff  to  produce  a  given  shade  than  a  soft  cook  does.     Although 


§5        PRACTICAL  APPLICATION  OF  DYESTUFFS        35 

groundwood  contains  a  higher  percentage  of  Hgnaceous  material 
than  unbleached  sulphite,  the  lignaceous  material  in  ground- 
wood  is  not  in  an  as  activel}^  combinable  state  as  in  unbleached 
sulphite;  it  is  for  this  reason  that  a  granite  effect  or  hairy- 
fibers  are  produced  in  mixed  furnishes  that  contain  unbleached 
sulphite  and  ground  wood. 

82.  Action  of  Basic  Dyestuffs  on  Rag  Stock. — Rag  stock  has 
very  little  affinity  for  basic  dyestuffs.  When  using  basic  dye- 
stuffs  on  such  stock,  a  certain  proportion  of  the  dyestuff  com- 
bines with  the  fibers,  and  a  certain  additional  amount  is  held  on 
the  fibers  by  the  size  and  alum;  but  the  back  waters  can  never 
be  cleared  up. 

83.  Action  of  Acid  Dyestuffs. — Since  acid  dyestuffs  have  no 
direct  affinity  for  any  type  of  cellulose  fibers,  being  mordanted 
to  the  fibers  by  the  use  of  size  and  alum,  thej'-  can  be  used  on  all 
types  of  stock  with  equal  success,  and  will  give  the  most  even 
dyeings  on  mixed  furnishes. 

84.  Action  of  Direct  Dyestuffs. — As  before  stated,  direct  (or 
substantive)  d^-estuffs  are  named  from  the  fact  that  they  have  a 
direct  affinity  for  cellulose  fibers.  The  greater  the  degree  of 
purity  of  the  fiber  the  greater  is  its  combining  power  with  direct 
dyestufi's;  for  which  reason,  they  color  most  efficiently  the 
bleached  rag  and  wood  pulps.  Owing  to  the  fact  that  the 
cellulose  fiber  in  groundwood  is  surrounded  by  other  material, 
the  direct  dj-estuffs  have  little  affinity  for  this  type  of  stock; 
and,  in  some  cases,  where  the  groundwood  is  coarse,  they  leave 
uncolored  shives  in  the  paper. 


MORDANTS 

85.  Use  of  Mordants. — A  mordant  combines  with  a  dyestuff 
on  or  within  the  fiber,  to  form  an  insoluble  compound;  in  other 
words,  it  fixes  the  dye.  The  paper  industry  does  not  use  mor- 
dants to  as  great  an  extent  as  the  textile  and  other  dye-consuming 
industries,  because  no  material  that  will  interfere  with  the 
sizing  of  the  sheet  may  be  added  in  the  manufacture  of  paper. 
The  size  and  alum  act  as  a  mordant  for  certain  dyestuffs,  the 
degree  of  mordanting  depending  on  the  kind  of  pulp,  method  of 
beating,  and  the  properties  of  the  dyestuff. 


36  COLORING  §5 

86.  Coloring  Unsized  Papers. — Because  of  the  affinity  of 
direct  dyostuffs  for  cellulose  fibers,  they  can  be  used  satisfactorily^ 
on  unsized  paper,  such  as  blotting  papers.  For  heavy  shades, 
however,  the  addition  of  40  or  50  pounds  of  salt  to  the  beater 
gives  a  greater  depth  of  shade  and  clearer  back  waters.  The 
action  of  salt  in  this  case,  however,  is  not  that  of  a  mordant — it 
acts  as  a  "salting  out"  agent. 

In  a  beater  containing  cellulose  fibers,  together  with  a  certain 
amount  of  water  holding  a  dj'estuff  in  solution,  if  a  more  soluble 
salt  be  added  to  the  beater,  it  will  tend  to  drive  a  less  soluble  salt 
of  the  same  base  out  of  solution.  The  addition  of  salt  tends  to 
throw  the  dyestuff  out  of  solution;  but,  on  account  of  the 
affinity  of  the  cellulose  fibers  for  this  dyestuff,  the  dj'-estuff  is 
forced  onto  the  fibers,  instead  of  being  crystallized  out  of  the 
solution.  Most  dyeings  with  direct  colors  are  brighter  on  unsized 
than  on  sized  papers,  because  the  sodium  salt  of  the  dyestuff  is 
much  brighter  than  the  aluminum  salt  that  is  formed  when  alum 
is  added  to  the  beaters. 

87.  Action  of  Size  and  Alum. — Acid  colors  are  mordanted  to 
the  fibers,  in  all  cases,  by  the  use  of  size  and  alum.  While  the 
presence  of  an  excess  of  alum  increases  the  retention  of  the  color 
on  the  fibers,  better  results  can  be  obtained  by  increasing  both 
size  and  alum  in  proper  proportions  rather  than  by  having  an 
excess  of  alum  only.  The  fact  that  heavier  sizing  increases  the 
shade  produced  by  acid  dyestuff s,  warrants  the  assumption  that 
the  greater  the  quantitj^  of  size  the  larger  the  number  of  particles 
there  are  to  which  the  color  may  become  attached,  or  by  which 
it  may  become  trapped  in  the  fibers.  Pigment  colors  behave 
in  a  manner  similar  to  acid  colors  in  this  respect,  far  better  results 
being  obtained  on  the  heavier  sized  than  on  the  lightly  sized 
papers. 

88.  Action    of    Soda    Ash,    Borax,    and   Other  Chemicals. — 

When  soda  ash  is  used  with  certain  direct  dyestuffs,  such  as  the 
various  brands  of  purpurines  and  Congo  reds,  or  borax  is  used 
with  such  acid  dyestuffs  as  metanil  yellow,  it  does  not  act  as 
a  mordant;  it  here  serves  to  neutralize  any  excess  of  alum  that 
has  been  added  to  size  the  paper,  in  cases  where  alum  has  a 
deleterious  effect  on  the  shade  of  the  dyestuff. 

89.  To  a  limited  degree,  other  chemicals  are  used  as  mordants 
for  specific  dyestuffs.     When  certain  direct  colors  are  treated 


§5        PRACTICAL  APPLICATION  OF  DYESTUFFS        37 

with  copper  sulphate,  their  fastness  to  Hght  is  greatly  increased; 
two  parts  of  copper  sulphate  should  be  used  for  every  one  part 
of  such  direct  dyestuffs.  Lead  acetate  decidedh^  improves  the 
brightness  and  fastness  of  such  phthalic  anhydride  dyestuffs 
as  eosine,  phloxine,  and  erj^throsine. 

90.  The  use  of  tannic  acid,  or  other  tannin-like  materials, 
decidedly  mordants  basic  dyestuffs  to  the  various  fibers.  The 
reason  their  use  has  not  been  more  completely  developed  in  the 
paper  industry  is  because  iron  has  the  property  of  darkening 
tannin;  hence,  trouble  is  experienced  on  account  of  this  darkening 
action,  and  the  paper  is  streaked  where  it  comes  into  contact 
with  iron. 

91.  After-Treatment  with  a  Mordant. — There  is  no  doubt 
but  that  after-treatment  of  the  colored  stock  with  the  proper 
mordant  would,  in  mam-  cases,  improve  the  fastness  to  light, 
two-sidedness  (see  Art.  106),  and  would  clear  up  the  back  waters. 
A  large  amount  of  work  is  still  to  be  done  in  connection  with  this 
subject  before  a  comprehensive  knowledge  of  proper  methods  for 
coloring  paper  is  obtained. 


ORDER  OF  FURNISH 

92.  Relation  of  Coloring  to  Furnish.— The  order  of  furnish  was 
discussed  in  the  Sections  on  Beating  and  Refining  and  in  Loading 
and  Engine  Sizing  but  it  is  well  again  to  consider  it  here  in 
connection  with  the  subject  of  coloring,  because  it  bears  an 
important  relation  to  this  subject.  It  must  be  borne  in  mind, 
however,  that  the  methods  emploj-ed  for  coloring  paper  are 
necessarily  subordinate  to  those  employed  to  obtain  the  maxi- 
mum production  of  paper  of  the  quality  desired,  using  the  equip- 
ment at  hand.  This  accounts  for  the  fact  that,  in  many  mills, 
efficient  coloring  methods  are  sacrificed  for  quantity  production. 
A  thorough  understanding  of  all  the  factors  affecting  production 
will  be  of  assistance  in  working  out  methods  that  will  give  the 
most  satisfactory  results  under  existing  mill  conditions. 

93.  Opinions  Regarding  Order  of  Furnish. — Opinions  differ  as 
to  the  proper  order  of  addition  (furnish)  of  stocks,  d^-estuffs,  size, 
alum,  fillers,  etc.  to  the  beater;  this  is  natural,  because  of  the 
varying  water  and  stock  conditions  at  different  mills.  In  cheaper 
grades  of  paper,  differences  in  the  quality  of  the  sheet  that  arise 


38  COLORING  §5 

from  failure  to  follow  the  best  methods  of  furnishing  are  less 
noticeable  than  in  the  higher  grades,  which  are  subjected  to  more 
rigid  tests,  both  as  regards  their  physical  properties  and  their 
appearance.  This  matter  will  here  be  first  discussed  on  the 
assumption  that  the  stock  furnished  is  of  one  tj^pe. 

94.  Stock  All  of  One  Type. — With  soft  water,  basic  dyestuffs 
should  be  added  before  the  size  and  ahmi.  If  the  water  is  com- 
paratively hard,  the  dyestuff  should  be  added  after  the  size  and 
alum ;  or,  a  small  quantity  of  the  alum,  sufficient  to  neutralize  the 
hardness,  should  be  added  before  the  dyestuff,  followed  by  the 
size  and  the  remainder  of  the  alum. 

With  acid  dyestuffs,  the  order  depends  upon  the  amount  of 
excess  alum  used  in  the  paper ;  if  only  sufficient  alum  be  used  to 
precipitate  the  size,  then  no  difference  will  be  perceived  between 
adding  the  dyestuff  before  or  after  the  size  and  alum;  but,  if  an 
excess  of  alum  be  used  in  the  beater,  better  results  will  be  obtained 
by  adding  the  dyestuff  after  the  size  and  alum. 

Direct  dyestuffs  should  always  be  added  to  the  beater  before 
the  size  and  alum;  because,  on  account  of  having  a  direct  affinity 
for  cellulose  fibers,  the  direct  dyestuff  should  be  allowed  to  come 
into  contact  with  the  fiber  before  it  is  coated  with  size  and  alum. 

Where  color  formulas  are  built  up  that  contain  basic  and  either 
acid  or  direct  dyestuffs,  the  acid  or  direct  dyestuffs  should  be 
added  to  the  beater  and  thoroughly  mixed  with  the  stock  before 
the  addition  of  the  basic  color  solution.  Where  both  acid  and 
direct  colors  are  used,  they  can  be  dissolved  together;  but  if  they 
are  dissolved  separately,  the  solution  of  direct  dyestuffs  should  be 
added  before  that  of  the  acid  dyestuffs. 

95.  A  General  Rule. — A  general  rule  for  the  addition  of  all 
chemicals,  such  as  copper  sulphate,  lead  acetate,  etc.,  is  to  add 
them  directly  after  the  dyestuff  and  before  the  size  and  alum; 
salt  should  also  be  added  immediately  after  the  dyestuff.  But, 
when  soda  ash  is  used,  it  is  an  open  question  as  to  whether  or  not 
it  should  be  added  before  or  after  the  size  and  alum.  (The 
authors,  personally,  do  not  believe  in  the  use  of  soda  ash,  for  the 
good  it  does  is  more  than  offset  by  its  deleterious  effects.)  When 
soda  ash  is  added  after  the  size  and  alum,  it  tends  to  dissociate 
the  aluminum  resinate,  and,  at  the  same  time,  to  replace  the 
aluminum  radical  in  the  dyestuff  with  the  sodium  radical.  Con- 
tinued beating  tends  to  increase  these  two  reactions,  with  the 


§5        PRACTICAL  APPLICATION  OF  DYESTUFFS        39 

result  that  the  degree  of  sizing  and  the  comparative  brightness 
in  shade  will  depend  upon  the  length  of  time  of  beating. 

96.  Mixed  Furnishes. — When  mixed  furnishes  are  used,  very 
careful  attention  must  be  paid  to  the  order  and  method  of  adding 
the  dyestuffs,  to  prevent  mottling.  With  basic  colors  on  a 
mixed  furnish  of  groundwood  and  unbleached  sulphite,  the 
groundwood  should  always  be  furnished  to  the  beater  first, 
followed  by  a  cold  solution  of  dyestuff,  unbleached  sulphite,  size, 
and  alum,  in  the  order  here  given.  On  mixed  furnishes  contain- 
ing wood  pulp  and  rag  stock,  direct  colors,  when  used,  should 
always  be  added  to  the  beater  in  a  cold  dilute  solution.  On 
account  of  the  nature  of  the  fiber,  rag  stock  is  always  furnished 
to  the  beater  before  the  wood  pulp;  consequently,  it  is  out  of  the 
question  to  consider  reversing  this  order,  for  the  sake  of  obtaining 
a  more  efficient  color  practice  at  a  decided  sacrifice  of  beater  prac- 
tice. In  order  to  prevent  mottling  on  such  mixed  furnishes  con- 
taining rag  stock,  where  direct  dyestuffs  are  used,  it  is  sometimes 
recommended  that  these  dyestuffs  be  added  to  the  beater  in  a  dry 
state  as  soon  as  the  beater  is  furnished. 

97.  Adding  Dyestuffs  in  Dry  State. — In  many  cases,  mill 
practice  has  designated  that  the  dyestuffs  be  added  to  the  beater 
in  a  dry  state;  but  such  practice  is  bound  to  result  in  a  slight 
increase  in  the  dirt  content  of  the  paper.  Although  the  dye- 
stuffs  of  reputable  manufacturers  are  very  clean,  it  is  impossible, 
in  the  case  of  any  commodity  that  must  be  ground  and  packed, 
to  keep  a  ver}^  small  amount  of  insoluble  matter  from  becoming 
mixed  with  the  dyestuff.  In  the  cheaper  grades  of  paper,  the 
amount  of  dirt  or  dust  from  the  dyestuff  will  be  inappreciable,  as 
compared  with  the  actual  dirt  in  the  pulp;  but,  in  the  higher 
grade  rag  papers,  this  small  amount  may  be  perceptible  at  times. 
For  the  above  reasons,  the  best  general  mill  rule  is  to  dissolve 
and  strain  all  dyestuffs. 

98.  An  Important  Point. — The  most  important  point  to 
remember  in  connection  with  the  whole  subject  of  order  of  furnish 
is  that,  once  a  furnish  and  formula  have  become  established, 
every  beater  making  that  order  must  be  handled  in  exactly  the 
same  manner. 

99.  Influence  of  Density. — The  density  of  the  stock  in  the 
beater,  which  varies  between  2.5%  and  8%  (depending  on  the 
nature  of  the  stock  and  the  type  of  the  beater),  has  a  very 


40  COLORING  §5 

decided  effect  on  the  coloring  power  of  certain  dyestuffs.  As  a 
general  rule,  the  greater  the  density  of  the  stock  in  the  beater  the 
greater  the  depth  of  shade  obtained  with  a  given  quantity  of  dye- 
stuff.  This  is  explained  by  the  fact  that  thorough  brushing  out 
of  the  fibers  has  a  tendency  to  work  the  dyestuff  into  the  fibers 
of  all  stocks  that  have  a  direct  afl^inity  for  the  dyestuff.  In 
the  case  of  acid  dyestuffs,  the  mordanting  action  of  the  size  and 
alum  on  the  dj^estuff  is  proportionately  increased  with  the 
densitv. 


COLOR  FORMULAS 

100.  Building  Up  Color  Formulas. — Every  beater  engineer  has 
his  own  individual  ideas  concerning  the  best  methods  for  building 
up  color  formulas;  this  is  due  to  the  fact  that  conditions  in  each 
mill  are  different,  both  in  regard  to  equipment  and  to  furnish. 
Before  deciding  upon  any  definite  plan  of  procedure,  the  beater 
engineer  must  have  a  real  appreciation  of  the  many  variables  that 
influence  the  shade  before  the  pulp  comes  off  the  machine  as 
colored  paper.  The  factors  that  must  be  taken  into  consider- 
ation are :  the  consistency^  (or  density)  of  the  stock  in  the  beater, 
method  of  beating,  type  of  dj^estuff  used,  the  effect  of  chemicals 
present,  action  of  colored  stock  in  chests,  loss  in  backwater,  color 
taken  up  bjj^  felts,  action  of  heat  of  dryers,  and  finish  of  the  paper. 

101.  Factors  to  be  Considered. — When  the  order  first  goes  into 
the  mill  to  make  a  certain  grade  and  shade  of  paper,  the  super- 
intendent or  beater  engineer  compares  the  shade  with  that  of 
samples  from  previous  runs.  If  a  run  has  been  made  that  closely 
approximates  this  shade,  he  can  start  coloring  his  beater  with  a 
formula  approximately  20%  less  than  the  one  used  on  his  previous 
run.  Consideration  must  be  given  at  this  point  to  the  matter  of 
amount  and  shade  of  broke  that  may  be  included  in  the  furnish. 
On  re-pulping  broke  in  the  beater,  it  loses  a  part  of  its  color 
strength,  the  amount  lost  depending  on  the  class  of  dyestuff  or 
pigment  used  in  coloring  it.  Colored  broke  should  be  distributed 
to  all  the  beaters,  not  all  dumped  into  one.  Allowance  must  be 
made  for  the  percentage  of  broke  in  the  furnish  and  the  pro- 
portion of  coloring  strength  retained.  Precaution  should  alwaj^s 
be  taken  to  see  that  too  much  dyestuff  be  not  added  at  the  start ;  it 
is  far  easier  to  add  color  to  the  beater  than  it  is  to  correct  for 
shade  when  the  strength  is  too  high.     The  dyestuff,  whether  in 


§5        PRACTICAL  APPLICATION  OF  DYESTUFFS        41 

the  form  of  dry  powder  or  in  water  solution,  should  not  all  be 
dumped  in  at  one  spot  in  the  beater,  but  should  be  allowed  to 
flow  in  gradually  during  one  complete  revolution  of  the  stock  in 
the  beater,  thus  giving  the  color  a  more  even  distribution. 

102.  Use  of  Laboratory  Matches. — In  case  the  beater  engineer 
has  no  guide  to  follow  from  previous  runs,  he  must  depend  upon  his 
laboratory  match  to  approximate  the  initial  amount  of  dyestuff 
he  should  add  to  the  beater.  In  case  the  mill  be  not  equipped 
with  laboratory  apparatus  for  matching  shades,  a  sample  should 
previously  have  been  sent  to  the  laboratory  of  one  of  the  dye- 
stuff  manufacturers,  to  obtain  an  approximate  formula.  It  is 
much  better  to  work  from  a  formula  with  individual  colors  in  the 
mill  than  to  have  a  sample  matched  by  a  color  house  and  a 
mixture  of  dyestuffs  sent  to  the  mill.  In  the  first  instance  if  there 
is  any  variation  in  the  stock,  water,  or  chemicals,  this  difference 
can  be  more  easily  overcome  by  the  use  of  one  or  more  of  the 
component  colors;  whereas  if  the  mixture  is  used,  the  shade  can 
be  varied  in  depth  only.  As  stated  in  Art.  71,  all  laboratory 
matches  are  approximations;  they  serve  their  purpose  by  acting 
as  guides  in  building  up  formulas  in  the  mill.  These  laboratory 
matches  should  be  cut  approximately  25 %  (Art.  70),  and  then 
built  up  with  one  dyestuff  or  another,  in  order  to  obtain  the 
correct  shade. 

Some  color  men,  however,  prefer  to  get  their  main  shade  by 
using  a  mixed  dyestuff,  and  to  give  this  any  final  variation 
necessary  to  compensate  for  the  factors  mentioned  by  adding 
more  of  one  or  the  other  of  the  component  dyestuffs. 

103.  Matching  Shades  in  the  Beater. — After  the  pulps,  color, 
size  and  alum  have  been  beaten  for  a  certain  length  of  time,  the 
shade  of  the  stock  in  the  beater  should  be  compared  with  a 
small  wet  portion  of  the  sample  to  be  matched.  Also,  a  hand 
sample,  as  previously  explained,  should  be  taken  from  the 
beater  and  dried,  and  compared  with  the  sample  to  be  matched. 
Only  continued  practice  in  the  matching  of  shades  in  the  beater 
will  give  the  beater  engineer  a  knowledge  of  just  how  a  shade  that 
has  been  brought  up  to  a  certain  point  in  the  beater  will  work  on 
the  paper  machine. 

That  the  first  few  pounds  of  paper  coming  over  the  machine 
may  be  of  the  same  shade  as  that  later  in  the  run,  it  is  sometimes 
necessary  to  color  up  the  white  water,  and  also  to  add  a  small 


42  COLORING  §5 

amouut  of  dyestuff  to  the  fan  pump,  to  compensate  for  the  color 
built  up  in  the  return  waters  later  in  the  run,  and  for  the  color 
absorbed  by  the  felts.  This  method  should  never  be  relied  on 
unless  the  beater  engineer  has  had  considerable  experience  in 
making  such  additions;  a  limited  experience  may  cause  far  more 
trouble  than  the  good  to  be  derived. 

104.  Doctoring  the  Shade. — As  soon  as  the  sheet  that  is 
representative  of  the  stock  in  the  chests  comes  over  the  paper 
machine,  a  comparison  with  the  sample  to  be  matched  will  show 
whether  the  shade  is  correct  or  whether  certain  additions  will 
have  to  be  made.  There  are  two  methods  of  making  these 
additions:  first,  coloring  the  chest;  second,  adding  an  extra 
amount  of  dyestuff  to  the  second  beater  to  compensate  for  the 
shortage  of  dyestuff  in  the  first  one  dropped.  Coloring  the  chest 
is  a  difficult  process  to  regulate;  it  should  be  avoided  whenever 
possible,  because  such  coloring  has  a  tendency  to  make  the  shade 
run  uneven.  However,  if  this  procedure  be  necessary,  the 
amount  of  stock  in  the  chests  is  estimated,  the  requisite  amount 
of  dyestuff  is  dissolved  in  a  very  dilute  solution,  and  this  solution 
is  slowly  added,  either  in  the  head  box  of  the  Jordan  or  directly 
into  the  chest. 

The  second  method,  that  of  dropping  a  beater  with  sufficient 
dyestuff  to  compensate  for  the  difference  in  shade  of  the  first 
beater,  is  very  satisfactory,  provided  there  is  proper  agitation 
in  the  stuff  chests.  In  any  mill  making  colored  papers,  it  is 
absolutely  necessary  to  have  good  agitation  in  the  chests;  other- 
wise, more  harm  than  good  is  done  by  trying  to  regulate  the 
shade  by  coloring  the  chest  or  by  dropping  the  second  beater. 
Further  changes  should  not  be  made  too  rapidly  after  color  or 
additional  stock  has  been  added  to  the  chest,  because  from  15  to 
30  minutes  is  necessary  to  obtain  the  true  value  of  these  changes 
over  the  average  paper  machine. 

The  second  beater  on  the  floor,  before  the  paper  first  comes 
over  the  machine,  should  always  contain  a  little  less  dyestuff 
than  the  first  beater;  for,  in  case  the  shade  may  come  a  little  too 
heavy,  the  second  beater  can  be  dropped,  which  will  compensate 
for  the  increase  in  shade  for  the  first  paper  over  the  machine  as 
compared  with  the  sample  submitted.  After  the  shade  is  once 
established  on  the  machine,  samples  of  the  finished  paper  should 
be  compared  at  frequent  intervals,  particularly,  if  there  be  any 
change  with  respect  to  the  basis  weight  or  finish  of  the  paper,  or 


§5        PRACTICAL  APPLICATION  OF  DYESTUFFS        43 

in  the  amount  of  suction  on  either  the  suction  roll  or  boxes;  and 
the  wet  stock  of  each  beater  on  the  floor  should  be  matched 
against  the  stock  in  the  stuff  chests. 

105.  Taking  Samples  from  the  Paper  Machine.— Insofar  as 
the  writer's  information  goes,  the  taking  of  samples  from  the 
paper  machine  for  the  purpose  of  comparing  the  uniformity  of 
the  run  in  regard  to  color,  has  not,  up  to  the  present  time,  been 
done  as  well  as  it  might  have  been.  The  uniformity  of  a  color 
run  is  most  effective]}^  observed  in  the  finishing  room  of  the  mill, 
where  the  whole  run  is  at  hand.  To  imitate  this  condition  in  the 
beater  room  while  making  the  paper,  two  methods  may  be  used : 

(a)  A  board  may  be  attached  to  the  wall,  on  which  is  a  row  of 
nails.  With  this  may  be  used  a  flat  piece  of  tin,  of  trapezoidal 
shape,  for  cutting  out  samples  of  paper,  the  samples  being  cut 
out  with  this  tin  as  they  are  taken  from  the  machine.  Order 
number,  date,  and  serial  number  (as  1,  2,  3,  and  4)  or  reel  number 
may  be  attached  to  each  sample  as  it  is  taken;  and  the  samples 
are  hung  up  on  the  board  on  the  wall  in  the  same  sequence  as  they 
were  taken  from  the  machine. 

(6)  A  second  method,  similar  to  the  preceding,  is  to  use  a  tin 
plate  of  rectangular  shape,  measuring  about  3  by  8  inches,  for 
cutting  out  samples  as  taken  from  the  machine.  As  before,  the 
samples  are  marked  with  the  order  number,  date,  and  serial  or 
reel  number;  but,  instead  of  hanging  them  on  a  board,  they  are 
kept  in  a  loose-leaf  folder. 

By  either  method,  the  samples  may  be  kept  indefinitely;  and 
any  irregularities  that  occur  during  the  run  of  the  paper  may  be 
noted  on  the  samples,  as  well  as  their  cause.  This  will  serve  as 
an  explanation,  if  such  be  asked  for  after  a  long  interval,  when 
the  details  of  the  run  may  have  been  forgotten  or  recollection 
may  be  hazy.  The  samples  are  also  useful  in  the  finishing  room,  as 
they  enable  the  boss  finisher  to  see  at  a  glance  whether  all  rolls  can 
be  cut  together ;  or,  if  a  non-uniformity  exists,  he  may  select  from 
these  samples  the  rolls  that  are  to  be  cut  together  on  the  cutter. 

106.  Two-Sidedness. — One  of  the  most  important  problems 
in  the  present  day  manufacture  of  paper  is  the  matter  of  two- 
sidedness,  by  which  is  meant  difference  in  shade  or  texture 
between  the  top  and  bottom  of  the  sheet.  The  degree  of  two- 
sidedness  depends  on  the  type  of  couch  roll  used,  the  number  of 
suction  boxes,  the  freeness  of  the  stock,  the  amount  of  water 


44  COLORING  §5 

carried  and  the  selection  of  the  dyestuffs.  A  Hmited  amount 
of  two-sidedness  is  absolutely  unavoidable  on  machines  where  a 
suction  couch  roll  is  employed.  This  trouble  is  caused  by  the 
fact  that  a  certain  proportion  of  the  dyestuff  used  to  obtain  any 
shade  is  merely  mechanically  fixed,  either  to  the  fiber  itself  or, 
as  in  the  case  of  acid  dyestuffs,  to  the  size  and  alum;  hence,  as  the 
paper  is  formed  on  the  wire  and  passed  over  the  suction  boxes 
and  suction  roll,  a  certain  amount  of  this  mechanically  fixed 
color  will  be  drawn  from  the  bottom  side  of  the  sheet.  Less 
trouble  in  this  respect  will  be  experienced  with  a  free  stock  than 
with  a  slow  stock. 

In  considering  this  problem,  it  is  obvious  that  the  extent  to 
which  two-sidedness  can  be  minimized  depends  on  the  selection 
of  dyestuffs  that  will  have  the  greatest  degree  of  adherence  to 
the  fibers.  The  degrees  of  affinity  of  different  classes  of  dye- 
stuffs  for  different  stocks  has  already  been  discussed.  On 
unbleached  pulpS;  with  basic  colors,  very  little  trouble  is  experi- 
enced with  two-sidedness,  because  of  the  direct  affinity  of  the 
basic  dyestuffs  themselves  for  the  lignaceous  material  in  the 
unbleached  pulps.  On  bleached  wood  pulps  and  rag  stocks, 
direct  colors  will  give  a  minimum  of  two-sidedness,  because  these 
colors  combine  directly  with  the  fiber. 

107.  Combinations  of  Dyestuffs. — When  selecting  combi- 
nations of  dyestuffs  for  any  given  shade,  those  should  be  selected 
which  have  the  same  degree  of  affinity  for  the  various  stocks  that 
are  used  in  the  furnish,  in  order  to  prevent  different  shades  of 
color  on  the  two  sides  of  the  sheet.  Because  of  the  fact  that 
pigment  colors  are  mechanically  fixed  within  the  sheet,  the 
two-sidedness  obtained  by  the  use  of  pigments  is  far  greater  than 
that  obtained  with  the  aniline  dyestuffs.  An  exception  is  in  the 
use  of  certain  pigments  made  from  anihne  dyestuffs,  which,  due 
to  admixture  with  certain  chemicals  in  their  process  of  manu- 
facture, more  or  less  mordant  such  colors  to  the  paper  fibers; 
hence,  they  have  less  two-sidedness  than  many  of  the  anihne 
dyestuffs  themselves.  By  proper  methods  of  sizing,  in  other 
words,  by  the  thorough  admixture  of  the  size  with  the  stock 
before  the  addition  of  alum  (preferably  added  in  a  dilute 
solution),  the  two-sided  effect  will  be  greatly  decreased. 

108.  Effect  of  Heat. — No  general  rules  apply  to  the  effect  of 
heat  on  the  various  groups  of  dyestuffs.     As  before  stated,  in 


§5        PRACTICAL  APPLICATION  OF  DYESTUFFS        45 

connection  with  the  dissolving  of  dyestuffs,  Art.  11,  no  basic 
colors  should  ever  be  heated  to  the  boiling  point.  In  certain 
cases,  for  example,  auramine  and  basic  or  Bismark  browns,  a 
temperature  limit  of  160°F.  for  the  dissolving  water  should  be 
adhered  to.  After  the  dyestuff  has  been  placed  in  the  beater, 
no  trouble  will  be  experienced  from  the  effect  of  heat  on  any 
color,  provided  the  temperature  is  not  raised  above  the  point 
that  will  affect  the  sizing.  On  the  paper  machine,  certain 
dyestuffs  have  the  property  of  changing  in  shade,  due  to  the 
heat  of  the  dryers.  The  manner  in  which  they  change  is  entirely 
individual  with  different  dyestuffs.  Chrysoidines  and  basic 
browns  in  sized  papers  have  a  tendency  to  be  redder  when  they 
first  come  off  the  machine  than  they  are  after  the  paper  has 
assumed  a  temperature  and  moisture  content  conforming  to 
atmospheric  conditions.  Certain  acid  colors  have  a  tendency 
to  burn  on  the  surface  of  the  sheet.  In  some  cases,  if  the  dryers 
are  too  hot,  this  burning  will  be  very  spotted,  and  it  will  practi- 
cally spoil  the  sheet.  Dyestuffs  that  have  a  tendency  to  spot 
should  be  avoided. 

With  acid  dyestuffs,  in  many  cases,  the  color  itself  is  very  much 
stronger  on  the  surface  than  in  the  middle  of  the  sheet ;  this  is  not 
a  disadvantage,  except  in  very  heavy  papers,  such  as  cover  papers. 
In  cases  of  direct  colors,  the  increase  or  difference  in  shade  caused  by 
the  heat  of  the  dryers  is  lost  as  soon  as  the  paper  is  in  equilibrium 
with  atmospheric  conditions.  For  this  reason,  when  matching 
shades  with  direct  colors,  it  is  a  good  policy  to  take  a  sample 
taken  from  the  machine  and  wave  it  in  the  air  for  4  or  5  minutes, 
(to  cool  it)  before  comparing  with  the  sample  to  be  matched. 

109.  Effect  of  Finish. — The  degree  and  type  of  finish  given 
the  paper  has  a  decided  effect  on  the  depth  of  shade  obtained  with 
a  given  quantity  of  dyestuff.  The  more  highly  calendered  the 
sheet  the  greater  will  be  the  depth  of  shade ;  in  other  words,  with 
a  given  quantity  of  dyestuff,  a  supercalendered  sheet  will  have 
the  appearance  of  being  much  more  heavily  dyed  than  a  machine- 
finished  sheet.  Water-finished  papers  have  the  appearance  of 
greatest  depth,  as  compared  with  any  other  type  of  finish.  As 
stated  before,  when  matching  the  highly  finished  sheets,  it  is 
necessary  to  steam  them  before  comparing  with  unfinished 
samples  coming  off  the  machine.  For  color  comparison,  samples 
should  be  taken,  whenever  possible,  from  the  run,  before  the 
paper  goes  through  the  calenders. 


46  COLORING  §5 

110.  Beater-Room  Practice. — The  general  rules  that  must  be 
followed  to  obtain  efficient  beater-room  practice  vary  with 
different  mills,  on  account  of  the  existing  conditions  as  to  equip- 
ment and  materials.  From  what  has  been  previously  stated,  a 
general  idea  of  efficient  operation,  as  applied  to  each  particular 
manufacturer,  may  be  obtained.  Attention  is  called  to  the 
following  points  because  of  their  application  to  anj^  situation: 

All  vessels  in  which  dyestuffs  are  dissolved  should  be 
thoroughly  cleaned  as  soon  as  they  have  been  used.  Except  in 
certain  special  cases,  dj^estuffs  should  always  be  dissolved  at 
temperatures  just  below  the  boiling  point  of  water,  and  they 
should  be  strained  before  adding  to  the  beater.  During  the 
process  of  packing,  as  well  as  when  opening  kegs  or  barrels  at 
the  mill,  small  quantities  of  dirt  and  insoluble  matter  are  liable 
to  become  mixed  with  the  dyestuff;  hence,  it  is  a  good  general 
rule  always  to  strain  the  dyestuff  solution.  Strainers  should  be 
kept  scrupulously  clean  and  should  be  inspected  frequently  for 
an}'  damage. 

When  once  a  formula  has  been  adopted,  it  is  most  essential 
that  the  order  of  addition  of  different  dyestuffs,  size,  alum,  fillers, 
etc.  be  strictly  adhered  to.  Samples  of  all  runs,  with  formulas 
attached,  should  be  kept  bj^  the  beater  engineer;  and,  on  each 
sample,  all  notations  regarding  speed  of  machine,  basis  weight, 
conditions  of  stock,  etc.  should  be  tabulated,  so  that  in  case 
another  run  is  made  that  requires  changing  the  formula,  an 
explanation  may  be  obtained  as  to  the  cause  of  such  change. 


CALENDER  AND  OTHER  METHODS  OF  COLORING 

111.  Calender  Coloring. — Calender  coloring  comes  next  in 
importance  to  coloring  in  the  beaters.  This  process  resembles 
staining  rather  than  actual  dyeing;  in  fact,  it  is  virtually  a  water 
finish,  in  which  a  color  solution  is  used  instead  of  water  only. 
In  calender  coloring,  the  dj^estuff  solution  is  allowed  to  flow 
constantly  into  one  or  more  water  or  color  boxes  on  the  calenders, 
this  solution  being  picked  up  through  the  rapidly  revolving 
calender  rolls  and  applied  to  the  surface  of  the  paper  as  it  passes 
between  these  rolls. 

112.  Low  Cost. — The  principal  advantage  of  calender  coloring 
is  its  low  cost.     Acid  dyestuffs  are  most  commonly  used  for 


§5        PRACTICAL  APPLICATION  OF  DYESTUFFS        47 

this  purpose  because  of  their  generally  good  solubility,  and 
because,  having  no  direct  affinity  for  cellulose  fibers,  the  shade 
produced  runs  more  uniform  than  with  any  other  class  of  dye- 
stuffs.  Acid  dyestuffs  are  also  more  stable  to  continued  temper- 
atures up  to  the  boiling  point,  which  sometimes  makes  their 
use  advantageous  in  this  type  of  coloring. 

113.  Calender  Coloring  with  Basic  and  Direct  Dyestuffs. — 
Basic  dyestuffs  are  sometimes  used  in  calender  coloring  in  those 
cases  where  extreme  brightness  and  minimum  cost  are  more 
important  than  uniformity  of  shade.  The  basic  dyestuffs  have 
a  tendency  to  mottle  and  streak  the  finished  paper,  and  to 
deteriorate  in  strength  upon  standing  in  the  hot  solution.  The 
direct  colors  are  also  used  occasionally  for  calender  coloring;  but 
these  also  have  a  tendency  to  streak  the  paper,  and  they  have 
neither  the  advantage  of  cost  nor  brightness  over  the  acid 
dyestuffs. 

114.  Apparatus  Employed. — The  apparatus  for  calender  color- 
ing consists  of:  a  tank,  or  barrel,  for  dissolving  the  dyestuff, 
into  which  runs  the  overflow  from  the  water  boxes;  a  solution 
storage  tank,-  which  is  set  on  a  platform  at  a  height  above  the 
top  of  the  calender  stack,  from  which  the  pipe  to  the  water 
boxes  is  led;  a  circulating  pump,  for  the  purpose  of  transferring 
the  solution  from  the  dissolving  or  overflow  tank  to  the  storage 
tank.  The  strength  of  the  dyestuff  solution  is  determined  by  the 
shade  required.  In  cases  where  the  shades  are  produced  by 
combinations  of  dyestuffs,  concentrated  solutions  of  the  indi- 
vidual dyestuffs  should  be  made  up  and  mixed  together  in  the 
dissolving  tank  until  the  proper  shade  is  obtained;  they  should 
then  be  diluted  to  the  proper  strength,  either  in  the  dissolving 
tank  or  in  the  storage  tank.  The  water  boxes  are  made  with 
one  side,  two  ends  and  a  bottom.  The  ends  are  shaped  to  fit 
closely  the  calender  roll  against  which  they  fit,  and  leakage  is 
prevented  by  rubber  packing  at  the  ends  and  a  rubber  lip  on 
the  edge  of  the  bottom.  The  box  is  set  against  the  upward 
turning  side  of  the  roll. 

115.  Formulas  for  Calender  Coloring. — The  following  proced- 
ure is  recommended  for  working  out  calender-coloring  formulas 
before  the  actual  run  is  started.  A  time  is  selected  when  the 
paper  going  over  the  machine  approximates  the  furnish  of  the 
paper  to  be  colored.     The  water  box  is  dammed  back  several 


48  COLORING  §5 

inches  from  the  edge  of  the  sheet,  and  the  color  solution,  which 
is  being  made  up  in  the  dissolving  tank,  is  poured  onto  the  face 
of  the  calender  roll,  where  the  sheet  is  running  dry.  This  gives 
the  same  effect  as  will  be  obtained  when  the  color  solution  is 
used  in  the  w^ater  boxes;  consequently,  by  changing  the  strength 
of  the  solution  and  the  relative  proportions  of  dyestuff  in  the 
dissolving  tank,  the  proper  formula  can  be  worked  out. 

As  soon  as  the  run  is  started,  the  color  solution  flows  from  the 
storage  tank  into  the  water  boxes,  on  either  or  both  sides  of  the 
sheet,  in  the  same  manner  as  water  is  applied  for  the  regular  water 
finish.  When  only  one  side  of  the  paper  is  to  be  colored,  water 
must  be  run  into  the  water  boxes  on  the  opposite  side  of  the  sheet, 
in  order  to  get  an  even  finish  and  to  counteract  curling. 

116.  Efficiency  of  Calender  Coloring. — The  degree  of  efficiency 
of  calender  coloring  depends  largely  upon  the  manipulation  of  the 
paper  before  it  reaches  the  calenders.  The  degree  of  sizing  also 
has  a  decided  effect  on  the  results  obtained.  If  the  paper  is 
slack  sized,  the  dyestuff  solution  will  penetrate  deepl}^  through 
the  surface,  giving  a  greater  depth  of  shade  than  is  the  case  with 
a  hard-sized  sheet;  it  will  also  make  the  paper  feel  damp,  and 
it  will  be  without  snap.  With  a  light  or  medium-sized  paper, 
only  one  color  box  is  necessary;  but,  with  a  hard-sized  sheet,  it 
is  sometimes  necessary  to  run  two  color  boxes,  in  order  that  the 
second  box  may  cover  up  the  light  spots  from  the  first  color  box, 
and  thus  give  a  uniform  shade.  The  degree  of  penetration  of 
the  color  solution  increases  with  the  temperature  of  the  solution 
and  the  heat  of  the  calender  stack;  hence,  in  order  to  obtain 
uniform  results,  these  two  factors  must  be  kept  constant.  A  well- 
formed  sheet  will  also  dye  more  evenly  than  a  wild  sheet,  because 
calender  coloring  accentuates  any  irregularities  in  the  paper  itself. 
Where  trouble  is  experienced  because  of  streaking  on  the 
calenders,  the  addition  of  a  small  amount  of  soap  in  the  dyestuff 
solution  will  usually  eliminate  this  difficult^^ 

117.  Combination  Method. — A  combination  method,  wherebj- 
the  coloring  is  done  partly  in  the  beater  and  partly  on  the 
calender,  is  often  used.  The  relative  proportion  of  the  two 
methods  thus  employed  depends  upon  the  cost  and  the  results 
desired.  The  principal  use  of  calender  coloring  is  on  different 
grades  of  box  boards  and  container  boards,  and  a  great  variety  of 
economical    shades   may    be    produced    on   this  type  of  stock. 


§5        PRACTICAL  APPLICATION  OF  DYESTUFFS        49 

Through  this  method  of  coloring,  different  shades  on  opposite  sides 
of  the  paper  or  board  can  be  produced  by  having  the  water  boxes  on 
opposite  sides  of  the  calender  stack  j&lled  with  different  dyestuff 
solutions.  Just  sufficient  solution  is  taken  up  by  the  sheet  to 
give  it  a  good  finish  on  the  calender  stack.  Sometimes  steam 
is  used  in  hollow  calender  rolls. 

118.  Tub  Coloring. — Tub  coloring  is  used  to  a  very  limited 
extent.  In  this  process,  the  paper,  in  a  semi-dry  condition,  is 
passed  through  a  tub,  situated  approximately  half  way  or  two- 
thirds  of  the  way  to  the  dry  end  of  the  machine;  and  after  passing 
through  this  bath,  and  then  through  squeeze  rolls,  it  is  dried. 
There  are  no  distinct  advantages  to  this  type  of  coloring;  it  is 
used  only  in  special  cases,  where  a  slight  saving  in  cost  over 
beater  coloring  can  be  made,  and  when  greater  penetration  can 
be  obtained  at  the  same  time  than  by  calender  coloring. 

119.  Oatmeal  Papers. — Oatmeal  papers  are  used  practically 
exclusively  for  wall  papers,  and  the  oatmeal  effect  may  be 
obtained  by  washing  a  suspension  of  wood  flour  over  the  surface 
of  the  sheet  on  the  wire.  In  a  majority  of  cases,  the  paper  itself 
is  highly  colored,  while  the  wood  flour  is  in  its  natural  state  of 
color.  In  some  cases,  however,  the  body  of  the  paper  is  white, 
while  the  wood  flour  is  colored  in  various  hues.  In  some  isolated 
cases,  ordinary  groundwood  is  used  in  place  of  the  flour,  but  this 
has  never  proved  satisfactor}-,  on  account  of  being  too  coarse. 
Dyestuffs  used  for  this  purpose  should  have  the  properties  of 
being  fairly  fast  to  light,  and  of  resistance  to  the  alkali  that  is  in 
the  paste  used  for  hanging  these  papers;  and  must  have  the 
property  of  not  bleeding,  in  order  to  prevent  the  wood  flour  from 
absorbing  the  dyestuff  in  the  paper.  On  account  of  the  require- 
ments just  mentioned,  direct  dyestuffs  are  generally  used  for 
this  type  of  work;  but,  by  careful  attention  to  their  method  of 
application,  certain  acid  and  basic  colors  are  used  very  efficiently. 
Another  method  is  to  mix  the  stock  in  separate  chests  and  bring 
them  together  in  a  specially  prepared  head  box  on  the  machine. 

120.  Mottled  or  Granite  Papers. — Granite  or  mottled  papers 
are  made  by  adding  a  small  percentage  of  highly  colored  fibers 
to  the  furnish.  The  amount  of  these  colored  fibers  ranges  from 
^%  to  3%,  depending  on  the  intensity  of  the  granite  effect 
desired.  The  colored  fibers  are  usually  made  bj-  dyeing  either 
rag    or    unbleached    sulphite  with  direct  colors.     The  colored 


50  COLORING  §5 

fibers  are  prepared  by  coloring  a  beater  of  stock,  in  the  regular 
manner,  with  direct  colors,  adding  40  to  50  pounds  of  salt  per 
1000  pounds  of  stock,  heating  to  140°F.,  cooling  to  below  100°F., 
adding  a  small  amount  of  size  and  alum,  and  then  subsequently 
running  the  stock  into  laps  on  a  wet  machine.  During  this  last 
procedure,  any  color  that  is  only  mechanically  fixed  to  the  fiber 
will  be  washed  out;  hence,  the  pulp  in  the  laps  will  not  bleed 
when  it  is  mixed  with  the  white  or  natural  stock,  in  the  production 
of  the  granite  papers. 

Very  good  effects  in  granite  papers  are  obtained  by  adding  to 
the  white  stock  two  or  three  different  shades  of  pulp  that  have 
been  colored  in  this  manner.  Where  the  granite  fibers  are  black 
in  color,  black  stockings  are  often  used.  Varied  effects  can  also 
be  obtained  by  using  wool,  jute  or  various  long  grass  fibers  in 
place  of  rag  or  unbleached  sulphite. 

121.  Blotting  Papers. — The  type  of  color  used  for  blotting 
papers  depends  upon  the  grade  or  furnish  of  the  paper.  In  the 
better  grades  of  blotting  paper,  manufactured  from  a  large 
percentage  of  rag  stock  and  sometimes  containing  a  small  amount 
of  soda  pulp  or  unbleached  sulphite,  direct  dyestuffs  should  be 
used  exclusivel}'.  In  the  verj^  cheap  grades  of  blotting  paper 
containing  unbleached  sulphite,  soda,  and  ground  wood,  basic 
colors  are  as  suitable  as  direct  dyestuffs. 

Direct  dyestuffs  can  be  more  efficiently  dj-ed  on  the  fiber  by 
the  addition  of  30  to  50  pounds  of  salt  per  1000  pounds  of  stock, 
and  raising  the  temperature  to  140°F.  The  addition  of  a 
minimum  of  10  pounds  of  soda  ash  tends  to  brighten  the  shade 
of  the  direct  dyestuffs,  and  it  has  no  injurious  effect  on  the  paper. 
The  objection  to  the  use  of  soda  ash  mentioned  previously  does 
not  apply  here,  as  the  paper  is  not  sized.  In  order  more  firmly 
to  fix  the  dyestuff  on  the  fiber,  it  is  the  practice  of  some  mills  to 
add  a  small  amount  of  alum  to  the  beater;  but  this  practice 
should  be  discouraged  for  two  reasons:  First,  any  quantity  of 
alum  over  |  %  to  1  %  has  the  property  of  destroying  the  blotting 
qualities  of  the  paper;  second,  as  stated  in  Art.  13,  alum  deadens 
the  shade  of  direct  dj^estuffs,  and,  in  the  presence  of  the  heat 
of  the  dryers,  it  often  tends  to  vary  the  shade  sufficiently  to  make 
uniform  results  difficult  to  obtain.  On  the  cheaper  grades  of 
blotting  paper  containing  groundwood,  the  addition  of  a  small 
quantity  of  alum  aids  materially  in  the  retention  and  uniformity. 
Because  of  the  fact  that  they  have  no  direct  affinity  for  any  fibers 


§5        PRACTICAL  APPLICATION  OF  DYESTUFFH        51 

and  require  a  mordant,  acid  colors  should  never  be  used  for  this 
type  of  work. 

122.  Duplex  Papers. — ^Duplex  papers  can  be  made  at  the 
calenders  of  a  Fourdrinier  machine  by  coloring  one  side  of  the 
calender.  In  the  case  of  two-ply  or  multiple-ply  sheets  made  on  a 
cjdinder  machine,  either  the  top  or  bottom  liner  or  both  can  be 
colored.  Duplex  sheets  can  also  be  made  on  a  Fourdrinier  or 
Harper  machine  by  having  a  vat  and  C3dinder  mold  attached  to 
the  paper  machine,  and  having  the  paper  from  this  cylinder  mold 
carried  bj^  a  felt,  so  as  to  meet  the  paper  from  the  machine  wire 
just  after  passing  through  the  couch  rolls,  where  the  two  papers 
are  pressed  together  into  the  duplex  sheet,  as  described  more 
fully  in  Section  1,  Vol.  V. 

123.  Spray  Dyeing.  — Spray  dj^eing  is  a  relatively  new  process ; 
and  it  is  only  within  the  last  few  years,  that  it  has  developed  to 
considerable  commercial  importance.  Its  advantage  lies  in  the 
fact  that  very  beautifully  colored  papers  can  be  produced  at  a 
low  cost,  with  a  minimum  consumption  of  dyestuff. 

Spray  dyeing  may  be  divided  into  two  types:  In  the  first  type, 
a  dyestuff  solution  is  sprayed  onto  the  sheet  of  paper  bj^  means 
of  a  spray  nozzle,  using  air  under  high  pressure  to  force  the 
color  solution  through  fine  orifices;  and  so  arranged  that  it  will 
strike  the  paper  either  before  or  after  passing  over  the  first 
suction  box,  depending  on  the  effect  desired.  In  the  second  type, 
the  d3^estuff  is  spattered  on  the  sheet  from  rotating  brushes, 
which  travel  through  the  dye  bath  and  then  against  a  baffle 
plate,  which  draws  back  the  hairs  of  the  brushes;  and  when  they 
pass  the  baffle  and  return  to  their  original  position,  the  color  is 
thrown  on  the  sheet.  Direct  dyestuffs  are  more  suitable  for 
this  work. 

124.  Cloudy  Effects. — There  are  numerous  methods  for 
obtaining  cloudy  effects,  either  by  washing  undyed  pulp  onto  a 
colored  stock  as  it  passes  over  the  machine  wire  or  by  coloring 
the  pulp  and  washing  it  onto  a  white  sheet;  in  either  case,  direct 
dyestuffs  should  be  used.  Where  the  stock  used  is  either 
unbleached  wood  pulp  or  groundwood,  basic  dyestuffs  may  be 
employed  for  coloring  the  body  of  the  sheet. 

125.  Crepe  Tissues. — Crepe  tissues  are  colored  by  the  dipping 
process,  which  is  the  same,  in  many  respects,  as  tub  coloring. 
This  coloring  is  done  at  the  same  time  as  the  creping  of  the  paper. 


52  COLORING  §5 

The  machine  required  consists  of  two  steel  rolls,  the  bottom  one 
of  which  is  covered  with  a  closely  woven  woolen  cloth  or  with 
rubber,  while  a  doctor  blade  crepes  the  paper  as  it  is  removed 
from  the  upper  steel  roll,  after  the  paper  has  passed  between  the 
two  rolls.  The  lower  roll  is  always  in  contact  with  the  dyestuff 
solution,  which  is  maintained  at  a  constant  level  in  the  color  box, 
in  which  this  lower  roll  revolves.  Acid  colors  are  most  suitable 
by  far  for  this  type  of  work,  because  of  their  even  dyeing  quahties; 
though  for  very  heavy  shades,  where  brightness  is  more  essential 
than  even  dyeing  qualities,  basic  colors  are  used.  Direct  dyestuffs 
are  employed  for  this  type  of  work  only  in  rare  cases,  where 
certain  fastness  properties  must  be  maintained. 

One  essential  in  the  coloring  of  crepe  tissues  is  to  maintain  a 
constant  temperature  of  the  dj^estuff  solution,  in  order  to  obtain 
a  uniform  depth  of  shade.  In  some  cases,  a  small  amount  of 
casein  is  added  to  the  dyestulT  solution,  as  it  causes  the  paper  to 
adhere  more  securely  to  the  upper  steel  roll,  and  gives  a  better 
creping  effect. 

126.  Parchment  Papers. — In  the  manufacture  of  parch- 
mentized  paper,  the  dyed  paper  is  passed  through  a  bath  of 
strong  sulphuric  acid.  Only  dyestuffs  that  will  not  be  affected 
by  sulphuric  acid  can  be  used  for  this  type  of  work.  The  tests 
referred  to  in  Art.  63,  will  indicate  the  action  of  each  dj^estuff 
against  acids,  alkahs,  etc.,  and  should  be  applied  when  making 
a  selection  of  dyestuffs  for  this  work.  The  most  secure  method 
is  to  submit  each  individual  problem  of  this  type  of  work  to  the 
laboratories  of  the  dyestuff  manufacturer. 

127.  Vulcanized  Papers. — In  the  manufacture  of  vulcanized 
papers,  the  dyestuff  used  must  not  be  affected  by  the  zinc 
chloride-hydrochloric  acid  solution  employed  in  vulcanizing. 
Certain  direct  dyestuffs  are  suitable  for  this  work;  but,  as  men- 
tioned in  Art.  126,  the  safest  way  is  to  submit  each  individual 
problem  to  the  laboratories  of  the  dyestuff  manufacturer. 


COLORING 


EXAMINATION  QUESTIONS 

(1)  (a)  Name  the  principal  groups  of  coloring  matters.  (6) 
Which  group  is  the  most  important,  and  why? 

(2)  What  are  the  distinguishing  characteristics  of  acid,  basic, 
and  direct  dyestuffs? 

(3)  What  particular  values  are  possessed  by  pigments  for 
coloring  paper,  considered  from  the  standpoint  of  (o)  cost? 
(6)  permanence?  (c)  tinctorial  power? 

(4)  How  is  Prussian  blue  formed?  Would  it  be  advisable  to 
use  it  for  coloring  soap  wrappers? 

(5)  Mention  the  principal  steps  in  producing  a  dyestuff 
from  coal. 

(6)  (a)  What  is  meant  by  standardizing  the  strength  of  a 
dyestuff?    (b)  How  is  this  necessary  operation  sometimes  abused? 

(7)  Explain  in  detail  how  to  determine  whether  a  particular 
color  is  a  single  dyestuff  or  a  mixture. 

(8)  Describe  a  method  for  estimating  the  coloring  power  of 
a  dyestuff. 

(9)  What  standard  solutions  should  be  kept  in  the  color 
testing  laboratory,  and  why  are  they  needed? 

(10)  (a)  What  classes  of  paper  should  be  fast  to  light?  (6) 
Is  change  of  color  always  due  to  the  dyestuff? 

(11)  After  making  laboratory  test  and  calculation,  what  pre- 
caution is  necessary  when  coloring  a  beaterfull  of  half-stuff? 

(12)  Mention  the  principal  parts  of  an  equipment  for  a  color 
room  in  a  paper  mill. 

(13)  Explain  the  dissolving  of  a  dyestuff. 

(14)  What  factors  affect  the  shade  of  a  paper. 

(15)  Explain  the  action  of  size  and  alum  when  coloring  paper. 

(16)  (a)  Explain  what  you  understand  by  mordanting;  (6) 
why  is  the  use  of  tannic  acid  for  this  purpose  objectionable? 

(17)  When  the  water  is  hard,  what  precaution  should  be 
taken  if  a  basic  dye  be  used? 

§5  53 


54  COLORING  §5 

(18)  How  does  the  density  of  the  stuff  in  the  beater  affect 
the  coloring? 

(19)  (a)  what  is  two  sidedness,  and  how  is  it  caused?  (6)  how 
can  it  be  minimized? 

(20)  Describe    the    process    (a)   of   calender  coloring;  (6)  of 
making  mottled  papers. 


SECTION  6 

PAPER-MAKING 
MACHINES 

(PART  1) 

By  J.  W.  Brassington 


THE  PAPER  MACHINE  AND  ITS  EQUIPMENT 


GENERAL  DESCRIPTION 

1.  Introductory. — The  object  of  this  Section  is  to  explain,  in  so 
far  as  is  possible,  the  best  methods  of  handling  a  paper  machine 
in  order  to  obtain  the  best  results,  both  as  regards  the  quantity 
and  the  quality  of  the  paper  produced.  It  is  not  the  aim  to 
train  paper-machine  designers,  but  to  impart  to  paper  makers 
the  essential  knowledge  regarding  the  construction  and  operation 
of  paper  machines  and  the  auxiliary  apparatus.  If  the  paper 
maker  finds  herein  real  information  as  to  causes  of  trouble  in 
paper-machine  operation  and  their  remedy,  and  hints  of  how  to 
improve  working  conditions,  and  of  how  to  avoid  trouble,  the 
purpose  of  this  Section  will  be  fulfilled.  The  information  here 
given  has  been  selected  from  the  advice  imparted  by,  and  the 
opinions  of,  practical  paper  makers  throughout  the  world.  It 
is  not  possible  to  record  here  all  the  information  thus  collected; 
hence,  only  the  most  important  facts  are  given.  The  student 
should  keep  his  own  notebook,  and  should  enter  in  it  all  interest- 
ing facts  that  come  up  in  the  course  of  his  experience,  particu- 
larly those  relating  to  any  troubles  that  arise,  their  cause,  and 
their  remedy.  The  mill  is  the  student's  laboratory,  and  his 
daily  work  a  series  of  demonstrations  and  experiments.  They 
should  be  recorded.  Such  a  notebook,  if  carefully  kept  and 
indexed,  will  be  of  great  value  and  assistance  in  his  future  work. 
§6  1 


PAPER-MAKING  MACHINES 


§6 


Before  explaining  in  detail  the  various  machines  and  appli- 
ances, it  is  advisable  to  trace  the  course  of  the  paper  through  the 
machine;  in  this  way,  a  knowledge  of  some  of  the  most  important 
features  concerning  the  manufacture  of  paper  will  be  impressed 
on  the  mind,  and  the  relationship  of  the  various  parts  to  one 
another  will  be  made  clear.  It  will  be  of  advantage  to  the 
student  to  give  careful  attention  to  the  following  article. 

2.  Course  of  Paper  through  Machine. — The  principal  parts 
of  the  modern  paper  machine,  and  the  course  of  the  paper  through 
it,  are  shown  diagrammatically  in  Fig.  1.  On  account  of  its 
length,  the  drawing  has  been  cut  in  two  in  the  middle,  the  right- 
hand  part  being  placed  below  the  left-hand  part.  Here  a  and  b 
indicate  the  same  point  when  the  two  parts  are  united. 


P     D  „ 


Fig.  1. 

The  first  section  (the  upper,  or  left-hand,  part)  is  called  the 
Fourdrinier  part,  or  wet  end;  this  will  be  described  first.  The 
stock  is  conducted  from  the  flow  box  X  over  an  oilcloth  or 
rubber  apron  to  the  wire  screen  A,  which  is  driven  by  the  couch 
roll  Bi,  and  is  supported  by  the  breast  roll  C,  table  rolls  D,  and 
wire  rolls  E.  The  deckle  straps  F  keep  the  stock  from  running 
off  the  edges  of  the  wire.  Much  water  drains  through  the  wire 
at  the  table  rolls,  more  water  is  taken  out  by  the  suction  boxes 
G,  and  the  fibers  are  laid  down  by  the  dandy  roll  H  (sometimes 
omitted)  and  the  couch  roll  B^.  If  a  suction  couch  roll  be  used, 
air  pressure  is  substituted  for  the  weight  of  the  upper  roll  jBo. 

The  second  section  (which  follows  the  wet-end  part)  is  called 
the  press  part.  Here  the  sheet  is  carried  by  the  felts  J\  and  Ji, 
and  passes  between  the  press  rolls  Ki,  K^  and  Kz,  Ki  (some 
machines  have  three  or  four  such  presses),  where  more  water  is 
squeezed  out,  the  sheet  is  further  pressed  and  is  prepared  for  a 


§6    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT      3 

smoother  finish.  The  felts  are  carried  on  rolls  L,  sometimes 
over  a  felt  suction  box  M.  The  direction  of  rotation  of  the  last 
press  is  usually  reversed,  so  as  to  give  the  paper  approximately 
the  same  surface  on  both  sides ;  and  where  the  course  of  the  paper 
is  thus  changed,  the  sheet  is  supported  by  paper-carrying  rolls  A^. 

From  the  presses,  the  paper  (now  containing  about  60%  to 
70%  of  water),  passes  to  the  dryers  P,  shown  in  the  lower  part  of 
the  illustration.  These  latter  are  steam-heated  cylinders;  the 
paper  is  kept  in  contact  with  their  hot  surfaces  by  cotton  (or 
canvas)  felts,  and  most  of  the  water  left  after  pressing  is  here 
evaporated.  The  number  and  the  size  of  the  dryers  varies  in 
accordance  with  the  weight  and  the  grade  of  the  paper,  and  with 
the  speed  of  the  machine.  The  opposite  side  of  the  sheet  is 
next  to  the  iron  on  successive  dryers,  thus  drying  the  paper  more 
evenly  and  giving  a  more  uniform  finish.  The  finished  sheet 
contains  from  7%  to  10%  of  moisture. 

Most  papers  are  finished  on  the  machine  by  passing  through 
the  calenders  R  {calender  stack).  These  constitute  a  set  of  very 
smooth  iron  rolls,  which  press  heavily  on  the  paper.  By  reason 
of  their  weight  and  the  friction  generated  when  the  paper  passes 
through  them,  the  paper  is  "ironed  out,"  as  it  were.  This 
operation  is  called  calendering.  The  web  is  then  wound  on  the 
reels  T,  of  which  there  are  several  types.  When  a  reel  is  full, 
the  paper  is  transferred  to  an  empty  one,  and  the  full  reel  is 
thrown  out  of  gear.  The  paper  from  the  full  reel  is  slit  into 
strips  by  revolving  slitters  and  wound  in  rolls  of  the  width  and 
diameter  desired.  The  slitter  is  shown  at  S  and  the  re-wound 
roll  at  W. 

The  several  sections  of  the  machine  must  be  capable  of  adjust- 
ment to  slight  variations  in  speed  in  relation  of  one  to  another, 
and  provision  is  also  made  for  varying  all  sections  in  unison. 
There  are  several  methods  of  driving  the  paper  machine,  and 
these  will  be  described  after  the  several  sections  just  mentioned 
have  been  explained  in  detail. 


PAPER-MACHINE  ROOM 

3.  Circulation  of  Stock. — Fig.  2  shows  a  paper-machine  wet-end 
in  plan  and  elevation.  The  vertical  stuff  chest  C  receives  the 
stock,  which  is  continually  agitated  in  it;  and  which  either  flows 
into  it  or  is  pumped  into  it  from  the  beater,  mixer,  or  beater 


PAPER-MAKING  MACHINES 


§6 


chest,  usually  passing  through  the  Jordan  engine.  The  stuff 
pump  A  delivers  the  stuff  from  the  stuff  chest  C  to  the  regulating 
box  B,  and  it  flows  from  the  latter  over  the  riffler  or  sand  trap 
D  to  the  screens  F  and  F.  In  the  case  of  stock  for  fine  rag  papers, 
it  also  passes  over  a  magnet  E  before  reaching  the  screens  F. 
The  screened  stock  passes  through  pipe  G  into  the  flow  box  H, 


X    V 


R 


K 


H 


L^ 


G 


W    ^M^ll        A 
C 


N~ 


v//////////////////////////h///////////////////////7/>/y///////W//////^^^^ 


ar 


E 


Fig.  2. 


from  whence  it  flows  upon  the  wire.  The  overflow  from  flow 
box  H  goes  to  the  white-water  box  W.  The  centrifugal  pump 
M  sucks  what  water  is  needed  to  dilute  the  stock  from  the 
white-water  box,  and  discharges  it  through  pipe  N  into  the 
regulating  box  B.  The  overflow  from  the  regulating  box  goes 
back  to  the  stuff  chest.  The  remainder  of  the  white  water  is 
generally  treated,  in  a  manner  to  be  described  later,  for  the 
recovery  of  fiber,  etc.  Attention  is  called  to  the  pump  S,  which 
is  here  shown  in  dotted  lines  because  it  is  under  the  machine- 


§6    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT      5 

room  floor  and  in  the  basement;  this  is  the  pump  that  main- 
tains a  vacuum  on  the  suction  boxes.  The  vacuum  system 
is  provided  with  a  separator,  for  removing  air  from  the  water 
that  is  drawn  from  the  paper. 

It  is  important  that  the  student  famiharize  himself  with  the 
circulation  of  the  stock  and  water,  using  Fig.  2  and  the  diagram 
in  Art.  21  as  guides,  and  that  he  keep  the  main  principles  of  this 
circulation  clear  in  his  mind. 

4.  Paper-Machine  Room  Details. — Stuff  chests  may  be 
horizontal  or  vertical,  and  there  maj^  be  one  or  two  to  a  machine. 
Both  stuff  chests  and  stuff  pumps  are  described  in  Section  3, 
Beating  and  Refining.  Plunger  stuff  pumps  may  be  single, 
double,  or  triple.  They  are  always  single  acting.  In  some 
mills,  centrifugal  pumps  are  used.  Pumps  with  1,  2,  or  3  plungers 
are  called  simplex,  duplex  and  triplex  respectively.  The  regulat- 
ing box,  of  which  there  are  several  patented  tj^pes  on  the  market, 
may  have  two,  three,  or  four  compartments.  The  rifflers  may 
be  simply  wooden  boxes  (troughs)  with  suitable  baffles  to  prevent 
the  passage  of  heavy  particles.  The  screens  may  be  flat  or  of  the 
rotary  type.  The  flow  box  may  have  two,  three,  or  four  com- 
partments; and  the  overflow  from  the  flow  box  may  go  to  the 
beater  chest  instead  of  to  the  white-water  box.  The  discharge 
of  white  water  from  the  centrifugal  pump  may  go  to  the  regulat- 
ing box,  to  the  beaters,  or  to  save-alls.  Every  mill  presents 
slight  differences  in  details  from  every  other  mill,  in  accordance 
with  the  ideas  of  the  man  in  charge.  The  student,  therefore, 
should  grasp  the  general  ideas  of  paper  making;  after  which,  he 
can  design  his  own  rifflers,  regulating  boxes,  etc.,  and  he  can 
choose  what  circulating  methods  he  prefers. 


IMPORTANT  AUXILIARY  EQUIPMENT 


STUFF  CHESTS 

5.  Description  of  Stuff  Chests. — The  stufiE  chest  is  a  large 
cylindrical-shaped  tank,  usually  vertical.  It  may  be  made  of 
iron,  wood,  or  concrete,  care  being  taken  that  the  interior  is 
smooth  and  that  there  are  no  corners  or  angles  for  the  stuff  to 
lodge  in.  Fig.  3  shows  a  vertical  stuff  chest,  and  Fig.  4  shows  a 
horizontal  stuff  chest.     The  central  shaft  revolves  at  a  moderate 


6  PAPER-MAKING  MACHINES  §6 

speed,  so  as  to  keep  the  pulp  thoroughly  mixed.  The  paddles 
make  from  15  to  20  r.p.m.  when  making  rag  papers.  If  the 
agitator  paddles  turn   too  rapidly,   they  tend   to  churn  light 


Fig.  3. 


fibers  into  soft  knots;  if  they  turn  too  slowly,  they  cause  variation 
in  weight  by  allowing  the  heavier  stock  to  settle.  More  detailed 
descriptions  of  Figs.  3,  4,  5  and  6  will  be  found  in  Section  3. 


§6    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT      7 

With  vertical  chests,  the  gearing  may  be  so  located  underneath 
them  that  dirt  and  grease  cannot  drop  into  them .  When  the  gear  is 
placed  below  the  chest,  a  stuffing  box  and  gland  are  used  to  prevent 
leakage.  This  type  of  stuffing  box  is  used  also  on  the  end  of  the 
shaft  that  extends  through  the  sides  of  horizontal  stuff  chests  to 
the  driving  mechanism.  A  good  design  of  stuff  chest  will  permit 
thorough  washing  and  complete  emptying,  so  as  not  to  waste 
stock. 


rSecHonA-A 


Fig.  4. 


6.  Capacity  and  Size  of  Stuff  Chests. — Vertical  stuff  chests  are 
generally  about  12  feet  in  diameter  and  from  6  to  14  feet  deep, 
according  to  the  size  of  the  machine.  A  stuff  chest  should  hold 
enough  (two  beatersful,  at  least,  especially  of  colored  stock)  to 
supply  the  paper  machine  for  an  hour  or  more,  and  to  give  plenty 
of  time  for  the  beaters  to  replace  their  contents.  If  the  stuff  in 
the  chest  is  allowed  to  run  low  between  charges  from  beaters  or 
mixers,  there  is  likely  to  be  variation  in  the  weight  of  the  paper, 
due  to  pulsations  in  the  chest.  The  consistency  of  the  stuff  in 
the  chest  is  from  2\%  to  3%.  The  stuff  in  the  beater  is  diluted 
by  the  water  required  to  wash  it  down  to  the  beater  or  Jordan 
chest — which  is  necessary  when  a  Jordan  is  used  and  where 
colored  papers  are  made. 

The  size  of  a  stuff  chest  is  readily  calculated.     For  example, 

suppose  a  machine  to  make  12  tons  of  paper  per  day  of  24  hours, 

and  it  is  desired  to  find  the  size  of  a  vertical  stuff  chest  for  this 

machine.     The  calculation  would  proceed  as  follows: 

.                            .       ,                       ,              ,               12  X  2000 
Average    amount    of    paper    made    per    hour  =  ^^ 

=  1000  lb.  The  beatershold,say  12001b.  of  paper  pulp;  and  since 
the  capacity  of  the  stuff  chest  must  be  at  least  2  beatersful,  it 
must  hold  1200  X  2  =  2400  lb.  of  paper.     Assuming  that  the 


8  PAPER-MAKING  MACHINES  §6 

consistency  of  the  stuff  is  2.4%,  the  weight  of  the  stuff  in  the 
chest  is  2400  -^  0.024  =  100,000  lb.,  a  cubic  foot  of  which  weighs 

from  62.5  to  63.0  lb.     Assuming  that  it  weighs  62.5=  ~v^~  lb., 

the    volume    of  the  chest  is  100,000  4-  -y^  =  100,000  X  -rnna 

16  1000 

=  1600  cu.  ft.  If  the  inside  diameter  of  the  chest  be  taken  as  12  ft., 
the  area  is  12'  X  0.7854  =  113.1—  sq.  ft.;  consequently,  the 
depth  of  the  chest  is  1600  ^  113.1  =  14.15  ft.,  say  Uh  ft. 

7.  Care  of  Stuff  Chests. — The  stuff  chests  should  be  well 
cleaned  whenever  there  is  an  opportunity  during  periods  that  the 
mill  is  shut  down ;  and,  particularly,  this  must  alwa3^s  be  done  when 
the  kind  of  paper  being  made  is  changed.  Wooden  stuff  chests 
that  are  not  in  use  should  be  kept  full  of  water,  being  freshly 
filled  at  intervals  of,  sa}',  three  or  four  weeks;  this  keeps  the 
wooden  staves  water  soaked,  and  it  prevents  leaks  and  deforma- 
tion. The  iron  straps  should  be  painted  periodically,  to  keep 
them  from  rusting.  Agitation  of  the  contents  of  a  stuff  chest  is 
very  important;  it  can  be  assisted  by  allowing  the  centrifugal 
pump  that  takes  from  the  Jordan  chest  to  discharge  tangentially 
into  the  stuff  chest,  thus  causing  the  stock  to  tend  to  flow  along  the 
outer  wall  of  the  chest.  This  method  is  only  applicable  to  very 
light  papers,  such  as  newsprint  or  cheap  magazine  papers.  A 
special  mixing  chest  for  newsprint  paper  is  described  in  the 
Section  on  Beating  and  Refining. 

8.  Horizontal  Stuff  Chests. — As  previously  stated,  stuff  chests 
may  be  horizontal  as  well  as  vertical.  Some  paper  makers  prefer 
a  horizontal  chest  having  a  series  of  vertically  acting  paddles, 
which  are  so  made  that  the  stuff  is  forced  one  way  along  the 
center  of  the  chest,  and  is  then  returned  the  other  way,  on  the 
outside,  near  the  shell.  This  result  is  obtained  by  reversing 
the  inclination  of  the  paddles  on  the  revolving  arms. 

In  mills  where  colored  papers  are  made,  horizontal  stuff  chests 
are  not  considered  to  be  a  good  installation.  When  a  color  is 
poor,  and  the  strength  or  brightness  of  the  color  is  to  be  "brought 
up"  or  intensified  by  adding  more  color  in  the  beaters,  horizontal 
stuff  chests  do  not  produce  results  on  the  machine  as  quickly  as 
vertical  stuff  chests;  the  contents  of  a  beater  do  not  "mix  in"  as 
quickly,  when  they  are  dumped  into  a  horizontal  stuff  chest. 
Furthermore,    the   horizontal    chest    has    the    disadvantage   of 


§6    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT      9 

spattering,  when  it  is  partly  full,  and  of  requiring  stuffing  boxes 
for  the  agitator  draft. 


STUFF  PUMPS 

9.  Description  of  Plunger  Pump. — The  contents  of  the  machine 
stuff  chest  are  pumped  to  the  regulating  box  by  the  stuff  pump, 
which  has  its  suction  pipe  connected  to  the  bottom  of  the  stuff 
chest.  Fig.  5  shows  a  simple  stuff  pump  of  the  usual  design;  a 
more  extended  description 
of  it  is  given  in  Section  3, 
Beating  and  Refining. 

Fig.  5  illustrates  a  single- 
acting,  single-cylinder, 
plunger  pump .  The  plunger 
A  is  moved  up  and  down 
by  the  revolutions  of  an 
eccentric.  As  the  plunger 
goes  up,  the  ball  valve  F  is 
lifted,  and  the  stuff  from  the 
stuff  chest  is  sucked  into  the 
space  D  and  into  the  pump 
cyhnder.  When  the  plunger 
reverses  its  movement  and 
goes  down,  the  ball  F  drops 
to  its  seat,  closing  the  open- 
ing, and  the  ball  valve  E  is, 
in  its  turn,  forced  off  its 
seat.  Liquid  equal  in  vol- 
ume to  the  volume  displaced 
by  the  plunger  during  its 
downward  movement  can- 
not now  find  room  in  space 
D,  and  it  is  therefore  forced 
to  flow  through  the  opening 
left  by  ball  E  into  the  dis- 
charge pipe  C,  which  delivers  it  to  the  regulating  box.  The 
pressure  forcing  the  liquid  through  the  discharge  pipe  is  that 
exerted  by  the  driving  eccentric  on  the  plunger.  When  the 
plunger  again  reverses,  beginning  its  upward  stroke,  the  pressure  of 
the  water  in  the  discharge  pipe  (the  back  pressure)  forces  ball  E 
to  its  seat,  and  thus  keeps  the  liquid  from  flowing  back  into  the 


Fig.  5. 


10  PAPER-MAKIXG.  MACHINES  §6 

cylinder.  This  type  of  plunger  pump  is  largely  used  on  machines 
of  small  size;  the  eccentric  is  keyed  to  a  revolving  shaft,  which  is 
driven  by  pulley  and  belt.  Hand  holes,  covered  by  plates  H, 
scn-e  for  replacing  balls,  cleaning,  etc. 

Double  and  triple  plunger  pumps,  of  the  same  valve  and 
cj'Under  design,  are  used  for  larger  machines  that  call  for  a  greater 
stuff-pump  dehvery  per  minute.  These  pumps  give  more 
impulses  per  minute,  and  there  is  a  more  regular  flow  of  liquid  and 
less  shock.  Except  that  they  are  gear  driven  instead  of  eccentric 
driven,  the  general  design  is  the  same  as  in  the  pump  just 
described.  The  advantage  of  using  gears  is  that  the  belt  pulley 
can  turn  faster  and  the  belt  used  may  be  smaller,  for  the  same 
power,  the  gears  reducing  the  speed  of  the  plunger  to  that 
desired. 

10.  Size  of  Pump. — It  was  previously  stated  (Art.  6)  that  the 
average  consistenc}^  of  the  stuff  in  the  chest,  and  which  is  to  be 
pumped,  is  about  2.5^;  that  is,  for  any  given  volume  of  stuff, 
approximately  2.-5  parts  are  pulp  and  97.5  parts  are  water,  which 
is  a  ratio  of  97.5  :  2.5  =  39  :  1.  In  other  words,  there  are  about 
40  lb.  of  water  to  1  lb.  of  pulp.  In  some  cases,  this  ratio 
may  be  as  high  as  50  :  1,  and  since  it  is  always  necessary  to  pro- 
vide for  extreme  cases,  this  last  ratio  will  be  taken  in  calculating 
the  size  of  the  pump  to  be  used.  Suppose,  as  in  Art.  6,  that  the 
machine  is  to  make  12  tons  of  paper  per  day  of  24  hours,  or  1000 
lb.  per  hour;  this  is  equivalent  to  1000  -^-  60  =  16|  lb.  per  min. 
The  plunger  of  the  stuff  pump  must  therefore  displace  approx- 
imately 16|  X  50  =  833^  lb.  of  stuff  per  min.  Taking  the  weight 
of  a  cubic  foot  of  the  stuff  as  62.5  lb.  =  ^^^  lb.,  the  volume  of  the 
stuff  delivered  by  the  pump  is  833|  -^  i?f^  =  833^  X  0.016  =  13^ 
cu.  ft.  per  min.  =  13^  X  1728  =  23,040  cu.  in.  per  min.  It  is  not 
good  practice  to  run  a  stuff  pump  over  30  r.p.m.,  which,  for  the 
single-acting,  simple  pump  just  described,  gives  30  working 
strokes  per  minute.  Consequentl}',  the  displacement  of  the 
plunger  per  stroke  (revolution,  in  this  case)  must  be,  at  the  very 
least,  23,OiO  -^  30  =  768  cu.  in.,  under  the  conditions  assumed. 
Since  in  1  U.  S.  gal.  there  are  231  cu.  in.,  the  plunger  must  displace 
768  -4-  231  =  3.32  gal.  per  stroke.  It  is  good  practice  to  use 
large  pumps,  since  they  can  be  run  more  slowly  and  will  last 
longer  without  repairs;  hence,  it  would  be  advisable  to  make  the 
displacement  of  this  pump  about  4  gal.  per  stroke.  A  cjdinder 
9  in.  in  diameter  and  15  in.  long  holds  4.13  gal.;  therefore,  the 


§6    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    11 

diameter  of  the  plunger  might  be  made  9  in.  and  the  stroke  might 
be  made  15  in.;  that  is,  the  pump  would  be  9  in.  X  15  in.  It  would 
not  be  advisable  to  use  a  smaller  cylinder,  because  no  allowance 
has  been  made  for  "slip."  In  any  case,  a  pump  must  have 
excess  capacity,  in  order  that  a  constant  head  be  maintained  on 
the  discharge  orifice  of  the  regulating  box,  the  overflow  from  the 
regulating  box  returning  to  the  stuff  chest. 

11.  Horsepower  of  Pumps. — When  calculating  the  horsepower 
required  to  pump  stuff,  it  is  important  to  remember  that  the 
pressure  required  to  pump  stuff  is  often  2|  times  as  great  as  that 
required  to  pump  water  against  the  same  lift,  because  of  the 
greater  friction  in  the  pipes. 

Assuming,  as  in  the  last  article,  that  the  pump  is  to  deliver  833^ 

lb.  of  stulT  per  min.,  and  also  assuming  that  the  total  lift  is  40 

833-  X  40 
ft.,  the  theoretical  horsepower  is       qq  nnn —  —  1-01  h.p.     This 

result  assumes  an  efficiency  of  100%;  but  the  actual  efficiency  of 
such  a  pump  will  not  exceed  about  50%,  and  the  actual  horsepower 
when  water  is  pumped  will  be  1.01  -r-  0.50  =  2.02  h.p.  When 
pumping  stuff,  however,  the  resistances  may  be  2.5  times  the 
resistances  when  pumping  water,  as  stated  in  the  last  paragraph; 
consequently,  the  actual  horsepower  is  2.02  X  2.5  =  5.05  h.p., 
or,  say  5  h.p. 

12.  The  Work  of  the  Stuff  Pump. — The  work  required  of  a 
stuff  pump  in  a  paper  mill  is  very  severe,  and  is  continuous.  The 
paper  maker  demands  a  reliable  pump, — one  that  will  always  do 
its  work  faithfull}^  under  exceptionally  trying  conditions, — and 
he  rightfully  claims  that  the  commercial  efficiency  of  a  fool-proof, 
reliable  stuff  pump  is  a  vital  essential  part  of  his  paper-making 
equipment.  The  stuff  pump  may  be  considered  the  heart  of  the 
paper  machine,  and  the  suction  pump  may  be  called  the  lungs; 
so  long  as  both  are  always  working  properly,  the  paper  maker 
does  not  grudge  them  a  comparatively  large  input  of  power. 

In  order  to  reduce  the  work  done  by  a  stuff  pump  for  any  given 
or  required  delivery, — thus  not  only  reducing  the  power  neces- 
sary to  drive  it  but  also  increasing  the  life  of  the  pump,  by  reliev- 
ing it  of  unnecessary  wear  and  tear, — it  is  always  advisable  to 
make  the  suction  pipe  of  ample  area  and  as  short  and  direct  as  is 
possible;  it  should  be  connected  to  the  bottom  of  the  stuff  chest, 
and  the  stuff  should  feed  into  the  pump  by  gravity  whenever 


12  PAPER-MAKING  MACHINES  §6 

practicable.  The  delivery  pipe  should  be  at  least  as  large  in 
diameter  as  the  discharge  outlet  of  the  pump,  and  as  much  larger 
as  is  convenient.  In  some  mills,  copper  or  brass  pipe  is  used  for 
conveying  the  stuff  so  as  to  minimize  contamination  by  iron. 

A  more  complete  treatment  of  the  subject  of  pumps  will  be 
found  in  the  Section  on  General  Mill  Equipment,  Vol.  V. 


THE  REGULATING  BOX 

13.  Functions  of  the  Regulating  Box. — Two  important  func- 
tions of  the  regulating  box  are:  first,  it  regulates  the  amount 
of  stock  going  to  the  paper  machine;  second,  it  regulates  the 
consistency  of  the  stock  going  to  the  paper  machine.  The  amount 
of  stock  is  regulated  by  so  operating  a  gate  or  valve  that  just  the 
right  amount  of  the  stock  which  is  pumped  from  the  machine 
stuff  chest  by  the  stuff  pump,  is  delivered  to  the  mixing  compart- 
ment or  mixing  box.  The  consistency  of  the  stock  is  regulated 
by  controlling  the  amount  of  M^ater  (usually  white  water  collected 
under  the  wire)  with  which  the  stock  is  diluted.  The  amount  of 
actual  fiber  delivered  by  the  stuff  pump  varies  with  the  consist- 
ency in  the  chest;  and  the  extent  of  the  dilution  must  be  changed 
in  accordance  with  the  freeness  of  the  stock  and  the  speed  of  the 
machine.  A  slow  stock  requires  less  dilution,  because  the  water 
then  stays  longer  with  the  fibers. 

14.  Uniformity  of  Weight  of  Paper. — In  the  earlier  types  of 
regulating  box,  the  machine  tender  changes  the  amount  of 
stock  going  to  the  machine  when  he  wishes  to  change  the  weight 
of  the  paper,  or  when  he  finds  that  the  weight  has  accidentally 
changed,  due  to  the  stock  in  the  chest  becoming  thicker  or 
thinner.  Likewise,  he  changes  the  amount  of  water  added  to  the 
stock  in  accordance  with  his  observation  of  its  behavior  on  the 
wire,  especially  during  the  formation  or  interweaving  of  the 
fibers.  This,  however,  is  only  one  of  several  adjustments  he  may 
have  to  make.  In  order  to  relieve  the  machine  tender  of  some 
of  this  responsibility,  and  to  get  more  dependable  uniformity, 
several  automatic  regulating  boxes  have  been  devised. 

The  principal  factor  in  securing  uniformity  of  weight  is  uni- 
formity of  the  consistency.  As  pointed  out  in  the  Section  on 
Beating  and  Refining,  the  logical  place  to  control  the  consistency 
is  when  the  stuff  passes  the  Jordan  on  its  way  to  the  machine 


S: 


S    w 


4^^^v^^v^^^^^'!'l^'A^^',^^^^^^^^^^^t 


T 


§6    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    13 

chest.     By  keeping  the  consistency  uniform,  regulation  at  the 
machine  is  greatly  simplified. 

15.  A  Simple  Regulating  Box. — A  very  simple  regulating  box 
is  shown  in  Fig.  6.  The  stuff  pump  discharges  through  pipe  E 
into  compartment  K.  An  adjustable  gate  G  admits  the  required 
amount  of  stock  to  the  mixing  compartment  or  box  M,  in  which 
it   is   diluted  and  mixed  with  white  _ 

water.  The  amount  of  the  white 
Vt^ater  admitted  is  controlled  by  a 
valve  on  pipe  W ,  set  by  the  machine 
tender  in  accordance  with  the  con- 
dition of  the  stock.  The  excess  stuff 
flows  over  partition  B  into  compart- 
ment F,  and  goes  back  to  the  stuff' 
chest  through  pipe  i7,  There  is 
usually  a  gate  on  the  discharge  L  to 
the  sand  trap,  screens,  and  machine. 
If  the  consistency  of  the  stuff  is  uni- 
form, this  gate  can  be  made  to  control 
the  amount  of  stock  furnished  the 
machine;  since  with  a  constant  head, 
the  volume  delivered  depends  only  on 
the  size  of  the  outlet.  It  may  here 
be  mentioned  that  stock  is  stuff  that 
has  been  diluted.  The  mixing  of  stuff 
and  white  water  may  take  place  in  a 
separate  stock  box. 

16.  Conditions  Governing  Automatic  Regulation. — Automatic 
regulation  involves  mechanical  regulation  at  one  or  more  of  four 
points:  (1)  admission  of  white  water  at  intake  of  stuff  pump;  (2) 
operation  of  gate  G,  Fig.  6;  (3)  control  of  valve  admitting  white 
water  to  mixing  box;  (4)  operation  of  gate  L.  The  principles 
generally  involved  are:  the  resistance  to  immersion  of  a  float, 
which  varies  with  changes  in  the  consistency  of  the  stock;  the 
friction  of  the  stock  as  it  passes  through  a  pipe,  which  varies 
with  the  consistency  of  the  stock;  the  slight  change  in  weight  of  a 
unit  of  volume  of  stock, which  results  from  changes  in  consistency. 

The  advantage  of  a  mechanical  automatic  regulator  is  that 
variations  in  consistency  are  detected  in  the  stock  before  it 
becomes  paper;  the  machine  tender  would  not  be  aware  of  these 


13- 


Fig.  6. 


14  PAPER-MAKING  MACHINES  §6 

variations  until  he  had  weighed  a  sample  of  the  finished  paper. 
However,  the  use  of  a  mechanical  automatic  regulator  does  not 
relieve  the  machine  tender  of  the  necessity  of  making  proper 
adjustments  when  changing  the  weight,  width,  or  speed  of  the 
paper,  or  in  preserving  the  general  character  of  the  stock.  The 
behavior  of  the  stock  on  the  wire  may  require  furthur  adjust- 
ment of  consistency. 

17.  Regulating  the  Consistency. — It  is  unnecessary  to  repeat 
here  the  description  of  the  consistency^  regulator,  which  was 
illustrated  and  explained  in  the  Sections  on  Treatment  of  Pulp, 
Vol.  Ill,  and  in  Beating  and  Refining.  The  regulator  there 
described  will  control  the  consistency  of  the  stuff  going  to  the 
machine  chest  to  within  5%  of  the  consistency  desired.  This  is 
accomplished  by  keeping  the  stuff  a  little  too  thick  in  the  beater 
or  pulp  chest,  and  bj^  controlling  the  amount  of  white  water  or 
fresh  water  admitted  to  the  suction  side  of  the  stuff  pump. 
With  stuff  of  accurately  controlled  consistency,  it  is  only  neces- 
sary for  the  machine  tender  to  set  his  valves  and  gates  for  the 
amount  of  stock  and  diluting  water  that  accords  with  the  speed 
of  the  machine  and  the  character  of  the  stock.  Variation  in  weight 
can  then  occur  only  because  of  mechanical  trouble  with  the  drive. 

18.  Automatic  Regulator. — In  Fig,  7,  a  regulator  is  shown 
which  has  been  designed  to  regulate  the  volume  of  stuff  furnished 
the  machine  as  the  consistency  varies,  in  order  that  the  weight  of 
fiber  supplied  to  the  machine  may  be  constant.  Delivery  from 
the  stuff  chest  is  through  the  pipe  A  to  box  B,  any  excess  flows 
over  the  dam  C,  and  is  pumped  or  flows  by  gravity  back  to  the 
machine  chest  through  pipe  D.  The  stuff  for  the  machine  passes 
the  adjustable  gate  E,  which  is  moved  by  pin  F  and  levers  G  and 
H,  the  latter  being  actuated  by  the  float  K.  The  stuff  passes 
down  the  spout  L,  works  up  around  the  float  K,  and  into  the 
annular  ring  M,  from  which  it  flows  to  the  machine.  The  float 
may  be  weighted  according  to  the  usual  consistency  of  the  stuff; 
it  sinks  in  thin  stuff,  and  it  is  raised  by  the  friction  and  greater 
density  of  thick  stuff,  thus  opening  or  closing  the  gate  E  accord- 
ingly. No  outside  power  is  required  to  operate  this  mechanism, 
which  is  very  simple.  The  amount  of  white  water  or  fresh  water 
used  to  dilute  the  stock  must  be  regulated  by  other  means. 

19.  Automatic  Stuff  Box. — The  regulator  shown  in  Fig.  8  is 
called   an   automatic   stuff   box.     Stuff  from   the   chest  enters 


§6    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    15 

compartment  A  and  leaves  it  through  outlet  F,  which  is  so 
divided  by  the  bottom  of  spout  H  that  a  part  or  all  of  the  stuff 


Fig.  7. 


may  go  either  to  the  overflow  or  back  to  the  chest  through  B, 
or  it  may  go  to  the  machine  through  C.  A  clean-out  gate  is 
shown  at  G;  it  is  operated  by  handle  T. 


Fig.  8. 


The  relative  proportions  of  the  stuff  going  through  B  and  C 
are  controUed  by  the  dividing  gate  K,  which  lets  more  stuff  into 
B  or  C,  according  as  this  gate  is  raised  or  lowered.     The  move- 


16  PAPER-MAKING  MACHINES  §6 

ment  of  gate  K  is  caused  by  the  float  M,  which  is  suspended  from 
the  levers  L.  When  the  stuff  is  coming  through,  the  gate  D  is  so 
adjusted  by  means  of  the  hand  wheel  E  that  the  required  amount 
goes  to  the  machine  and  the  remainder  goes  back  to  the  chest. 
The  float  is  counterpoised  by  the  weight  W,  which  is  adjusted  to 
balance  the  float  in  stock  of  the  proper  consistency.  If  the  stock 
becomes  thicker,  less  fluid,  its  buoyant  action  is  increased,  the 
float  rises,  and  the  gate  K,  which  is  attached  to  it,  also  rises; 
the  changed  opening  thus  obtained  admits  less  stuff  to  the 
machine  and  more  to  the  chest.  If  the  stuff  becomes  thinner, 
more  fluid,  more  of  it  will  then  be  required  on  the  machine;  its 
buoyant  action  then  decreases,  and  the  float  M  falls.  This 
causes  the  gate  K  to  move  downward,  partially  closing  the  open- 
ing to  the  chest,  which  sends  less  stock  to  the  chest  and  more  to 
the  machine.  The  stuff  may  be  thinned  to  the  proper  state  of 
dilution  for  machine  operation  by  adding  water  at  any  conveni- 
ent point  after  the  stuff  leaves  the  stuff  box.  The  regulation  of 
this  water  is  not  provided  for  in  this  apparatus,  since  the  slight 
change  in  the  flow  of  stuff  required  to  maintain  uniform  weight 
of  paper  would  make  only  an  almost  imperceptible  change  in 
the  density  of  the  stock  on  the  wire. 


SAVE-ALLS 


20.  White  Water. — White  water  is  the  term  used  to  designate 
the  water  that  flows  through  the  wire  of  the  paper  machine  and 
into  the  save-all  boxes  under  the  wire;  it  is  the  water  that  is 
removed  by  the  table  rolls  as  the  paper  forms,  and  by  the  suction 
boxes.  Naturally,  this  water  contains  considerable  fiber  and 
filler,  and  it  should  not  be  wasted. 

As  the  white  water  collects  in  the  save-all  boxes,  it  flows,  b}^ 
means  of  wooden  troughs,  to  the  back,  or  driving  side,  of  the 
Fourdrinier  and  into  a  box  that  is  piped  to  the  suction  intake  of  a 
centrifugal  pump.  This  pump  discharges  as  much  white  water 
into  the  regulating  box  as  is  required  to  dilute  the  stuff  in  com- 
partment M,  Fig.  C.  This  constant  circulation  is  also  main- 
tained in  the  case  of  a  cylinder  or  board  machine.  There  is, 
however,  a  comparatively  large  proportion  of  the  white  water 
that  escapes  the  save-all  boxes;  this  settles  in  a  pit  under  the 
wet  end  of  the  machine,  or  it  flows  over  the  dams  of  a  cylinder 
machine.     It  is  often  necessar}^  to  permit  quite  a  large  quantity 


§6    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    17 

of  stuff  to  flow  to  the  pit;  and  if  there  is  no  means  of  recovering 
this  waste,  it  ultimately  finds  its  way  to  the  sewer. 

21.  Paper -Mill  White  Water  Flow  Diagram.— A  typical  paper 
mill  system  is  drawn  for  machines  having  trays  and  is  shown  with 


Shfffrom  Chefif 

906  6. 
?.6% 
I3&.26T. 


Regulating  Box 


Excess  SucVion 


9316.  0.1111%  &2ST 


f 


Wafer 
F.W.I07G. 

F.w.iooe. 
F.w.sooe.  ■ 

300G. 


Mixing    Box 


4793  6. 

0.628% 

1811 


Sci 


43006. 
181  T 


Head  Box 


1 


■^^ 


SOOOG. 

0.602% 

181  T 


Wi 


1231 G 
0  0845% 
6.2ST. 


1820. 
l2°/o 
130  T. 


Presses 


To  While  Wafer  Sysiem 


130  T. 
33% 


Dryers 


127.31 
92% 


3775  6. 

0194% 

441 


1^ 


tray  and  suction  water  supplied  to  a  mixing  box  having  baffles  so 
arranged  that  all  the  tray  water  is  used  before  any  of  the  suction 
water.  The  supply  to  the  machine  includes  groundwood  and 
sulphite  pulp,  the  worked-up  "broke"  and  the  recovered  stock 


18 


PAPER-MAKING  MACHINES 


§6 


from  the  excess  white  water.  The  stock  is  shown  as  "air-dry" 
consistencies  up  to  the  dryers,  purposely  to  bring  out  the  "book 
figure"  shrinkage  between  the  "air-dry"  pulp  and  the  finished 
paper.  This  diagram  shows  where  and  how  much  fresh  water 
is  added,  how  much  white  water  is  removed,  how  much  fiber 
is  contained  in  it,  and  where  it  re-enters  the  system  or  is  dis- 
charged. The  width  of  the  stream  is  proportional  to  the  volume. 
Of  course,  if  consistency  figures  vary  from  those  given — and 
they  usually  will,  the  volume  of  water  flow  must  be  changed  in 
proportion. 

In  this  diagram,  which  is  drawn  for  a  120-ton  newsprint  unit, 
the  following  abbreviations  are  used: 

F.  W.  =  fresh  water 

G  =  gallons  per  minute 

%  =  consistency,  air  dry. 

T  =  tons  per  24  hours,  including  "broke." 

A  sulphite-mill  system  serves  as  a  good  outlet  for  excess  paper 
mill  white  water.  For  a  25-ton  pulp  mill,  500  to  600  gallons 
per  minute  of  the  paper-mill  water  carrying,  say,  3  tons  of  stock, 
could  be  used  to  advantage.     Under  this  condition  the  loss  from 

the    sulphite    mill  will  be 
js\M  greater ;  but  still  about  80  % 

of  the  stock  in  the  paper- 
mill  water  will  be  retained 
with  the  sulphite  stock. 
The  use  of  this  paper-mill 
water  also  may  necessitate 
added  deckering  or  press- 
ing equipment  for  the 
sulphite,  mainly  due  to 
slowing  up  the  stock. 

22.  Cylinder  Type  of 
Save  -All.  —  Several  types 
of  save -alls  are  fully  de- 
scribed in  the  Section  on  Treatment  of  Pulp,  Vol.  Ill,  one  of 
these  being  shown  in  Fig.  9.  Here,  a  cylinder  4,  covered  with 
fine  wire,  is  revolved  in  a  vat  8,  into  which  the  white  water 
flows,  generally  by  gravity,  through  inlet  7.  The  white  water 
flows  through  the  fine  wire  covering  of  the  cylinder  mold,  leaving 
the  suspended  fibers  clinging  to  the  outside  surface.     As  the 


Fig.  9. 


§6     THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    19 

surface  of  the  revolving  cylinder  emerges  out  of  the  water,  it 
passes  under  a  soft  couch  roll  2,  which  picks  off  the  adhering 


fibers  from  the  wire.     The  couch  roll  is,  in  turn,  scraped  by  a 
wooden  doctor  1,  which  is  so  inclined  that  the  pulp  fibers  are 


20  PAPER-:\IAKIXG  MACHINES  §6 

taken  off  the  couch  roll  and  guided  by  a  board  3  into  a  passage  10. 
From  this  passage,  pulp  fibers  thus  scraped  off  are  conducted 
to  a  convenient  receptacle,  as  a  truck,  from  which  the  pulp  is 
shoveled  into  the  beaters,  or  conducted  in  suspension  to  the  white- 
water  or  stock  sj^stem. 

]\Ian3^  developments  of  this  type  of  save-all  are  in  use.  Fig. 
10  shows  a  polygonal  drum  7,  wound  wdth  brass  wire,  which  is 
covered  for  five-sixths  of  its  perimeter  by  a  part  of  the  endless 
felt  8,  in  order  to  save  a  larger  proportion  of  the  finer  fibers. 
This  felt  is  of  considerable  length;  it  is  carried  out  of  the  top  of 
the  vat  on  rolls,  and  the  fibers  are  washed  off  by  a  shower  pipe 
at  a  convenient  point,  or  are  scraped  from  a  couch  roll,  as  at  22. 
In  another  type,  the  collected  fiber  is  blown  off  the  face  of  the 
cylinder  by  means  of  a  current  of  compressed  air,  which  is 
discharged  through  a  perforated  pipe  in  a  tangential  direction 
against  the  outside  of  the  cylinder. 

Fig.  11  shows  a  cj^Hnder  revolving  in  a  vat  of  white  w^ater  19. 

By  means  of  interior  air-tight  compartments,  w'hich  are  connected 

to  a  suction  pump,  the  water  is  pulled  thi'ough  the  wire,  and  the 

fibers  are  left  behind  on  the  surface  of  the 

wire  when  the  air-tight  compartments  are 

under  water.     At  a  certain  point,  18,  when 

these  air-tight  compartments  are  out  of  the 

water,  they  connect  with  the  discharge  of  an 

air  pump,  and  the  fibers  are  blown  off  the 

surface  of  the  wire,  to  slide  dow-n  the  doctor 

Fig.  11.  6.     This  type  of  machine  is  also  used  to 

thicken  pulp. 

23.  In  all  these  machines,  with  the  exception  of  the  save-all 
where  the  felt  is  used,  there  is  Httle  or  no  salvage  of  the  finer 
fibers  and  of  the  filling  materials,  such  as  clay,  because  these 
find  their  way  through  the  mesh  of  the  cylinder-wire  covering. 
Where  the  felt  is  used,  the  loss  due  to  the  wear  of  the  felt  and  to 
the  expense  of  attendance  (this  latter  item  being  chargeable  to 
all  types  of  save-alls)  becomes  an  important  consideration. 

24.  Settling  Tanks. — A  very  important  type  of  save-all  that 
is  largely  used  in  book-paper  mills  is  called  the  settling  tank; 
its  first  cost  is  expensive,  but  this  is  more  than  compensated  for 
by  the  small  cost  of  operation,  upkeep,  and  repair,  with  no  parts 
to  wear  out  or  require  renewing. 


§6    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    21 


To  take  care  of  all  the  white  water  from  a  pulp  or  paper  mill, 
the  settling  tanks  must  be  of  large  proportions,  in  order  to  give 
all  the  white  water  sufficient  time  to  stand  long  enough  to  settle. 
In  some  cases,  the  white  water  is  distributed  around  an  annular 


Fig.  13. 


Fig.  14. 


Fig.  15. 


/ 


\ 


Fig.   16. 


Fig.  17. 


trough,  Fig.  12,  running  on  the  outside  circumference  of  the  tank. 
When  full,  this  annular  trough  allows  the  white  water  to  flow 
slowly  over  into  the  tank,  so  as  to  prevent  any  undue  agitation 
and  permit  the  maximum  settling  effect.     This  type  of  save-all  is 


22  PAPER-MAKING  MACHINES  §6 

made  conical  in  shape,  the  apex  of  the  cone  being  the  lowermost 
point,  at  which  the  sediment  is  removed  through  a  valve. 

Fig.  13  shows  a  more  modern  type,  in  which  the  white  water 
enters  at  the  center,  and  flows  outwardly  into  a  series  of  annular 
troughs  until  it  reaches  the  outer  trough,  where  the  solids  finally 
settle  in  the  bottom  of  the  inverted  cone. 

The  settling  type  of  save-all  possesses  the  advantage  of 
allowing  the  savings  to  be  pumped  back  into  the  sj^stem,  thus 
eliminating  the  labor  involved  in  the  save-alls  previously 
described,  where  the  savings  are  so  thick  that  it  is  necessary  to 
shovel  them  into  trucks,  from  which  they  must  then  be  forked 
into  the  beaters.  Settling  tanks  must  be  large  enough  to  permit 
their  uninterrupted  operation,  in  order  that  the  white  water  may 
flow  continuously  into  the  tank,  while  the  savings  and  clear 
water  are  flowing  away  continuously  and  separateh\  This 
requires  that  the  tanks  be  about  20  feet  in  diameter  and  that  the 
cone  be  about  the  same  height,  though  even  larger  dimensions 
are  preferable.  The  settling  tank  does  not  work  right  until  it 
becomes  full  of  white  water,  when  the  incoming  water  comes 
quickly  to  rest  on  top  of  the  large  body  of  water  beneath  it,  and 
then  the  suspended  matter  begins  to  settle  at  once. 

25.  Inclined-Wire  Save-Alls. — A  commonly  used  type  of  save- 
all,  which  is  made  in  many  different  forms,  is  easily  built  in  the 
mill,  and  requires  little  or  no  power  to  drive  it,  is  an  inclined 
screen,  of  fine  mesh  wire,  which  is  sometimes  given  ashght  motion; 
it  requires  only  intermittent  attention,  which  involves  merely  the 
pouring  of  the  white  water.  This  type  needs  practicalh^  no 
attention  at  all,  since  the  savings  can  be  pumped  back  into  the 
system  in  the  same  manner  as  in  the  settling  tank,  the  wire  screen 
replacing  the  settling  action.  It  also  has  the  advantage  of  low 
first  cost.  Figs.  14-17  show  diagrammatically  four  forms  of 
this  type. 

26.  Fig.  14  shows  the  Whitham  type.  The  diameter  of  the 
cone  at  the  top  is  about  11  feet  the  diameter  of  the  opening  at  the 
bottom  is  about  2  feet  and  the  height  of  the  cone  is  about  10  feet 
The  speed  of  revolution,  about  6r.p.m.,  is  not  important;  it  simply 
revolves  fast  enough  to  allow  the  showers  to  clean  the  face  of  the 
wire.  While  the  wires  should  be  about  120  mesh,  to  save  the 
maximum  of  fiber,  they  are  often  as  coarse  as  80  mesh,  or,  even, 
60  mesh. 


§6     THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    23 

A  save-all  of  this  type,  and  of  the  dimensions  given,  can  handle 
about  400  gallons  of  waste  water  per  minute,  which  is  the  average 
amount  of  white  water  from  a  paper  machine  making  50  tons  of 
paper  per  day  of  24  hours,  about  4500  pounds  of  paper  per  hour. 
The  two  figures  are  given,  because  the  hourly  figure  is  the  max- 
imum output,  while  the  daily  figure  is  the  average  output 
when  allowance  is  made  for  breaks,  etc. 

The  save-all  shown  in  Fig.  15  is  similar  to  that  of  Fig.  14, 
except  that  the  cone  is  inverted  from  its  former  position,  and  the 
showers  are  on  the  outside,  the  water  flowing  on  the  outside  of  the 
cone  instead  of  down  the  inside,  as  in  the  case  of  the  former. 

The  most  important  thing  in  connection  with  an  inclined  save- 
all  is  the  cleaning  of  the  wire.  If  the  cleaning  is  intermittent,  it 
should  be  done  at  least  once  every  8  hours. 

27.  Fig.  16  shows  the  Nash  type  of  save-all,  in  which  the  cone  is 
replaced  by  a  flat  vibrating  screen,  situated  at  such  an  angle  that 
the  entering  water  flows  down  and  through  the  screen;  the  sav- 
ings are  left  on  the  surface,  to  be  washed  off  by  a  shower  pipe. 

The  Shevlin  type  of  save-all  is  shown  in  Fig.  17.  It  consists  of 
a  revolving,  fine-wire-mesh  covered  cylinder  that  contains  a 
revolving  worm.  As  the  white  water  flows  in  at  one  end,  the 
clear  water  escapes  through  the  wire  mesh,  and  leaves  the  savings 
in  the  interior;  the  screw  (worm)  gradually  forces  the  savings 
along  the  interior  of  the  cylinder  until  they  are  delivered  out  at 
the  other  end,  where  they  fall  into  a  suitable  receptacle,  from 
which  they  are  pumped  back  into  the  system. 

28.  Save-Alls  as  Filters. — The  savings  and  rejections  may  be 
pumped  separately  into  the  system  at  convenient  points,  or  they 
may  be  permitted  to  run  to  waste,  as  desired.  The  save-all  is 
sometimes  used  for  straining  or  filtering  purposes,  in  which  case, 
the  clear  water  that  passes  through  the  wire  can  be  pumped  into 
the  water  system  that  serves  the  mill,  and  the  savings  may  be 
dirt  that  is  allowed  to  fall  from  the  screen  save-all  to  waste. 

The  wire  mesh  that  is  used  in  the  construction  of  these  save-alls 
must  be  well  supported  with  wire  of  about  14  mesh,  to  keep 
in  shape;  the  only  part  that  requires  renewing  is  the  fine 
wire,  as  it  wears  out;  this  is  a  good  place  to  make  use  of  old 
Fourdrinier  wire.  The  capacitj^  of  the  wire  type  of  save-all, 
when  used  as  a  filter,  is  practically  unlimited;  a  save-all  of  the  size 
mentioned  in  Art.  26  will  filter  2,000,000  gallons  of  water  from  all 


24  PAPER-MAKING  MACHINES  §6 

solid  impurities  in  24  hours,  and  it  will  supply  water  for  paper- 
machine  showers  and  for  similar  purposes.  The  power  required 
to  drive  this  save-all  is  very  small,  a  maximum  of  3  h.p.  being 
sufficient. 

RIFFLERS,  OR  SAND  TRAPS 

29.  Construction. — Rifflers,  or  sand  traps,  are  wood  troughs 
through  which  the  stock  flows  from  the  regulating  box  to  the 
screens.  They  vary  in  size  and  length,  and  in  shape,  according 
to  the  capacity  of  the  machine  and  the  relative  position  of  the 
regulating  box  with  respect  to  the  screens.  Note  the  position  of 
the  riffler  in  Fig.  2. 

The  bottom  of  the  trap  (riffler)  is  divided  into  sections  by 
transverse  strips  of  wood,  which  are  frequently  so  inclined  that 
their  faces  lean  against  the  flow  of  the  stock;  this  helps  in  the 
retention  of  dirt,  or  sand,  as  it  sinks  to  the  bottom  of  the  riffler. 
In  some  narrow  boxes,  the  wood  strips  are  replaced  with  strips  of 
zinc,  slipped  into  slots  in  the  sides  of  the  trap;  these  can  easily  be 
removed  for  cleaning.  The  depth  of  the  riffler,  or  sand  trap,  is 
from  18  to  20  inches,  and  the  width  is  from  18  inches  to  8  feet. 
The  narrower  sizes  are  usually  of  greater  length,  say  from  30  to  50 
feet;  while  the  rifflers  called  button  catchers  may  be  longer,  even, 
than  50  feet,  when  they  are  used  to  catch  stitching  wires  in  mills 
that  prepare  the  stuff  from  old  magazines.  The  wider  traps  are 
seldom  over  15  feet  long,  being  used  in  the  preparation  of  fine 
writing  and  bond  papers.  The  bottom  of  the  trap  is  sometimes 
covered  with  old  felt,  to  catch  and  hold  the  dirt,  but  this  is  of 
doubtful  value.  The  rifflers  should  be  carefully  cleaned  whenever 
the  mill  is  shut  down.  If  felts  are  used  on  the  bottom  of  the 
riffler,  they  should  be  nailed  down  between  the  slats  and  carried 
up  the  sides,  so  that  no  dirt  or  stuff  can  accumulate  underneath 
and  break  away  at  intervals,  to  cause  breaks  on  the  machine. 

For  the  purpose  of  controlling  the  amount  of  water  in  the  stuff, 
there  may  be  two  pipes  at  the  inlet  to  the  riffler,  one  for  water 
and  one  for  pulp  from  the  regulating  box,  when  the  stuff  is  not 
diluted  in  the  regulating  box  or  in  a  special  mixing  box. 

30.  Two-Run  Riffler. — Fig.  18  shows  one  type  of  riffler,  or 
sand  trap.  The  mixed  water  and  fiber  flows  into  the  riffler 
through  pipe  A,  and  the  pitch  (slope)  of  the  bottom  of  the  riffler 
is  only  about  1  inch  in  14  feet.     Observe  the  shape  of  the  strips  J5 


§G     THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    25 

that  catch  the  heavier  particles  of  sand.  This  riffler  is  divided 
into  two  runs  by  the  central  dividing  board  D,  the  total  length  of 
run  of  the  stock  being  about  28  feet,  and  the  width  of  each  run 
being  about  18  inches.  The  discharge  pipe  C  leads  to  the  screens. 
When  the  riffler  is  to  be  cleaned,  the  discharge  pipe  C  is  dis- 
connected, the  supply  pipe  A  is  put  to  one  side,  and  the  riffler  is 
turned  on  its  side,  or  even  upside  down,  so  a  hose  can  be  played 
into  it  and  the  dirt  washed  out.  By  turning  the  handle  H,  the 
worm  W  turns  the  worm  wheel  Wi,  and  moves  the  riffler  over  as 
far  as  is  required.  The  worm  wheel  Wi  is  keyed  to  the  gudgeon 
(journal)  G. 


Fig.   18. 


Other  types  of  rifflers  are  illustrated  and  explained  in  .  the 
Section  on  Treatment  of  Pulp,  Vol.  III.  Since  rifflers  are  often 
made  at  the  mill,  local  ideas  and  conditions  may  affect  their  con- 
struction. The  student  should  refer  to  Figs.  1  and  2  constantly, 
to  familiarize  himself  with  the  circulation  of  the  stuff  from  the 
stuff  chest  until  it  becomes  stock  on  the  rifflers  and  is  delivered  to 
the  machine. 

31.  Riflflers  with  Electromagnets. — Paper  stock  that  is  pre- 
pared from  rags,  especially  if  overalls  are  used,  is  likely  to  contain 
small  particles  of  iron.  This  may  also  occur  when  waste  papers, 
stitched  with  wire,  are  used.  Particles  of  iron  may  likewise  be 
present  by  reason  of  the  abrasion  of  beater  and  Jordan  bars. 
Such  particles  can  be  almost  entirely  removed  from  the  diluted 
stock  by  placing  an  electromagnet  across  the  riffler,  just  before 
the  stock  goes  to  the  screens.  When  this  is  done,  it  is  a  good 
plan  to  make  the  riffler  a  wide,  short  box,  in  which  the  magnet  is 


26 


PAPER-MAKING  MACHINES 


placed,  in  order  to  have  a  shallow  stream  of  water  flowing  over 
the  magnet.     A  good  installation  is  shown  in  Fig.  19. 

Here  ^  is  a  stream  of  stock  in  the  riffler  5;  C  is  an  adjustable 
baffle;  arrow  D  shows  the  direction  of  flow  of  the  stock;  E,  E  are 
magnet  pole  pieces;  F,  F  are  magnet  coils;  G  is  a  yoke  connecting 
the  two  pole  pieces;  //  is  a  wood  support  for  the  extractor;  and 


Fig.   19. 


K  and  L  are  the  lead  wires.  A  plugged  hole  in  the  bottom  or 
side  of  the  magnet  affords  an  opening  for  cleaning,  when  the 
current  is  off.     Direct  currrent  is  equired  for  an  electromagnet. 


SCREENS 

32.  Diaphragm  Screens. — Before  the  paper  stock  finally 
enters  the  flow  box,  or  head  box,  as  it  is  sometimes  called,  ready 
to  flow  onto  the  wire  of  the  paper  machine,  it  is  screened,  for  the 
purpose  of  removing  as  much  as  is  possible  of  the  dirt,  lumps, 
slivers,  etc.  that  may  be  present,  and  which  have  resulted  from  or 
have  escaped  during  the  process  of  preparation.     Both  the  flat, 


§6    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    27 

or  diaphragm,  and  the  rotary  types  of  screens  are  used  at  this 
stage  of  manufacture.  In  either  case,  a  difference  in  level 
between  the  inside  and  the  outside  of  the  screens  causes  the  water 
in  which  the  fiber  is  suspended  to  pass  through  a  slotted  or 
perforated  plate. 

In  Fig.  20,  the  diaphragm  screen  is  made  to  take  10,  12,  or  14 
plates,  usually  of  bronze,  which  are  12  inches  wide,  43  inches  long, 
and  about  |  inch  thick.  These  plates  12  form  the  top  of  a  shallow 
box,  the  bottom  of  which  is  made  up  of  a  series  of  rubber  dia- 
phragms 22,  which  are  supported  on  boards  14  and  are  separated 
by  wood  spacers  21,  which,  together  with  the  strips  30,  support  the 
plates.  The  top  of  this  shallow  box  is  the  bottom  of  the  screen 
box,  the  sides  and  ends  of  which  are  numbered  10  in  the 
illustration.  The  screen  box  rests  on  the  frame  18,  to  which  the 
diaphragms  are  nailed.  The  box  and  frame  are  clamped  together 
by  long  threaded  bolts  (screen  bolts)  in  such  a  manner  as  to 
make  a  tight  joint  all  around.  Two  socket  joints  are  provided 
on  one  side,  so  the  box  can  be  raised  at  intervals  and  washed  with 
a  hose.  The  diaphragms,  which  give  the  screen  its  name,  are 
fastened  by  air-tight  joints  to  the  sides  and  ends  of  the  box  and 
to  the  cross  beams  19.  Rods  5,  attached  by  blocks  23  to  the 
centers  of  the  diaphragm  boards  15,  and  bearing  at  their  lower  ends 
a  hard-wood  toe  block  7,  ride  cams  8,  which  have  three  or  four 
corners.  The  cams  are  mounted  on  a  shaft  2,  which  revolves  at 
125  to  175  r.p.m.,  thus  agitating  each  diaphragm  either  three  or 
four  times  for  each  revolution  of  a  cam.  The  cams  are  so 
mounted  on  the  shaft  that  their  strokes  alternate  with  one 
another.  The  hard-wood  blocks,  usually  maple,  are  held  by 
clamps  9;  they  are  removable,  since  they  require  replacing  as 
they  wear  out.  The  blocks  are  restrained  from  jumping  away 
from  the  cams  by  the  springs  27  and  28,  and  by  the  adjusting 
nuts  4. 

33.  The  size  of  the  slots  in  the  screen  plates  depends  upon  the 
land  of  paper  being  made,  their  width  ranging  frorn  8  to  25 
thousandths  of  an  inch  (0.008"-0.025");  they  are  referred  to  as  8 
cut,  25  cut,  etc.  The  slots  are  wider  at  the  bottom  than  at  the 
top,  and  are  cut  about  4  or  5  to  the  inch;  their  length  is  about  4 
inches.  The  screen  is  made  with  an  adjustable  dam  31,  32  at  the 
outlet  16,  to  permit  complete  control  of  the  level  of  the  stock 
relative  to  the  plates.  The  position  of  the  plates  being  fixed,  the 
use  of  the  adjustable  dam  board  32  allows  the  operator  to  back 


28 


PAPER-MAKING  MACHINES 


§6 


§6    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    29 

up  the  water  and  stock  under  the  plates  until  the  screening  action 
is  satisfactory.  If  the  stock  level  is  too  high,  the  diaphragm  will 
shoot  the  stock  back  through  the  plates;  if  the  level  is  too  low, 
the  capacity  of  the  screen  is  decreased,  as  there  must  be  enough 
surge  to  keep  fibers  from  settling  thickly  on  the  slots.  The 
operator  should  adjust  the  dam  while  he  looks  down  on  the  screen, 
while  the  screen  is  in  operation.  Sometimes  a  variation  in  the 
sizes  of  the  slots  in  the  different  plates  is  successfully  used  to 
increase  the  capacity  of  a  screen.  When  this  is  done,  the  oncom- 
ing stock  is  forced  to  foUow  a  definite  path,  mapped  out  with 
baffles.  The  plates  hadng  the  larger  slots  are  near  the  recei^-ing 
end,  where  the  stock  flows  freely  and  rapidly;  the  plates  ha^-ing 
the  smaller  slots  are  at  the  other  end,  where  the  flow  of  the 
stock  is  retarded  and  the  stock  has  nearly  finished  its 
journey.  Stock  is  nearly  always  dehvered  to  a  screen  at  one 
end,  there  being  a  slight  slope  downwards  of  the  plate  surface  to 
the  other  end. 

Screens  should  always  be  kept  clean;  otherwise,  they  soon 
become  filled  with  stock.  This  not  only  decreases  the  capacity 
of  the  screen  but  it  also  increases  the  danger  of  lumps  of  stock 
accumulating.  In  time,  these  lumps  get  into  the  flow  box  11, 
Fig.  20,  from  which  they  find  their  way  to  the  paper  machine 
and  are  a  frequent  cause  of  breaks. 

34.  Care  of  Screens. — The  screen  plates  are  often  ruined  by 
careless  workmen  during  the  operation  of  cleaning.  Walking 
on  the  screens  in  hobnail  boots  (which  catch  in  the  slots),  and 
banging  the  plates  with  hammers  or  pieces  of  belting,  may  force 
through  the  plates  the  material  to  be  removed;  but  it  is  very 
likel}-  to  injure  the  plates,  and  the  slots  may  be  appreciably 
enlarged.  The  only  right  way  to  clean  screen  plates  is  to  raise 
the  screen  and  patiently  clear  each  slot  with  the  cleaning  tool 
that  is  suppUed  by  the  screen-plate  makers,  and  which  is  just 
large  enough  to  go  into  the  slots.  The  plates  should  then  be  well 
washed  with  a  hose. 

The  screens  should  be  well  washed  at  least  once  a  week;  this 
means  that  the  boxes  must  be  Hfted  out,  the  slots  cleaned,  and 
the  interior  of  the  diaphragms  and  aU  inner  parts  of  the  screen 
boxes  thoroughly  cleaned  of  all  slime  and  traces  of  old  stock. 
If  this  be  not  done  periodically,  the  dirt,  shme,  and  accumulations 
of  stock  win  get  on  the  wire  and  cause  many  unnecessary  breaks 
and  much  spotted  paper.     The  slime  that  coUects  lq  the  screens 


30  PAPER-MAKING  MACHINES  §6 

is  a  peculiarly  fertile  source  of  trouble;  it  forms  a  transparent 
spot,  which  will  generally  become  a  hole  somewhere  on  the 
machine.     These  slime  spots  are  a  sign  of  dirtj^  screens. 

It  is  well  to  have  a  set  of  boxes  for  each  screen,  with  plates 
of  different  cut.  It  may  even  be  desirable  to  have  a  duplicate 
box  for  each  screen,  to  allow  a  clean  screen  to  be  put  in  place 
quickly,  especially  when  using  long  rag  stock.  Care  should  be 
taken  that  the  screen  diaphragms  work  right;  see  that  the  outlet 
dams  are  properly  adjusted,  and  be  sure  that  the  hard-wood 
blocks  do  not  ride,  for,  if  they  do,  they  cannot  give  the  diaphragm 
the  proper  range  of  action. 

The  use  of  a  shower  of  water  to  wash  the  large  slivers,  shives, 
and  dirt  to  the  lower  end  of  the  screen  is  preferable  to,  and  gen- 
erall}^  quite  as  satisfactory^  as,  the  use  of  scrapers.  If  scrapers 
are  used,  they  should  be  made  of  softer  material  than  the  metal 
of  the  screen  plates.  The  plates  should  be  carefully  handled  and 
cleaned;  and,  if  the  slots  are  enlarged  by  reason  of  excessive 
cleaning,  the  plates  should  be  discarded.  Screen-plate  manu- 
facturers can  re-cut  old  plates  to  some  standard  slot  size. 
The  screws  must  fit  in  the  spacer  pieces  and  sills,  so  each  screen 
plate  may  be  rigidly  held  in  its  place.  It  is  almost  impossible 
to  keep  screwed  screen  plates  in  condition  after  the  sill  screw- 
holes  get  worn;  in  any  case,  there  is  a  tendency  for  small  screws  to 
get  lost  or  badly  strained  when  the  screens  are  cleaned.  There 
are  many  designs  of  screwless  screen  plates,  which  are  fastened 
in  place  by  beveled  or  rabbited  cleats  that  fit  specially  edged 
screen  plates.  If  not  too  complicated,  all  such  designs  are 
superior  to  the  screw  type. 

Care  should  be  taken  to  screw  or  clamp  securely  to  the  screen 
frame  the  top  box  that  carries  the  plates,  using  a  good  water- 
tight packing.  The  diaphragm  screen  is  still  very  commonly 
used,  in  spite  of  many  obvious  drawbacks. 

35.  Rotary  Screens. — Many  paper  makers  prefer  rotary 
screens  because,  with  this  type,  it  is  possible  to  keep  the  screen 
plates  continuously  clean  by  means  of  a  good  shower.  It  is 
only  of  late  j'^ears  that  rotary  screens  of  simple  design  and  heavy 
construction,  qualified  to  give  large  capacity  and  long  service, 
have  been  available.  Several  makes  of  rotary  screens  that  are 
proving  satisfactory  in  operation  are  now  on  the  market.  They 
are  of  two  types ;  namely,  the  inward-flow  screen,  and  the  out- 
ward-flow screen.     Both  have  their  own  peculiar  method  of 


§6     THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    31 


agitating  the  stock,  to  assist  it  in  flowing  through  the  plates  and 
in  preventing  the  settKng  of  fiber. 

The  inward-flow  type  of  rotary  screen  is  naturally  of  greater 
capacity  than  the  outward-flow  type,  and  it  is  best  adapted  to 
screening  dirty  stock.  It  is  used  for  newsprint,  book,  sulphite 
bonds,  bag,  wrapping,  board,  roofing,  and  coarse  papers  generally. 
The  outward-flow  screen  is  better  suited  to  the  making  of  fine 
papers,  such  as  ledgers,  fine  writings,  and  bond  papers  containing 
a  large  proportion  of  rag  stock. 

36.  Inward -Flow  Rotary  Screens. — Fig.  21,  is  an  end  view 
of  a  frequently  used  inward-flow  rotary  screen.  The  stock 
enters  through  flow  boxes  A  and  B,  both  being  placed 
above  the  vat  and  discharging  downwards  against  a  revolving 
cylinder  C.  The  stock  passes  through  the  screens  that  form  the 
shell  of  the  cylinder,  and  it  then  flows  through  an  open  journal  to 
a  discharge  box  at  the  rear 
end,  which  is  connected  to 
the  flow  box  of  the  paper 
machine.  There  is  a  dif- 
ference of  level  between  the 
stock  that  is  inside  and  that 
which  is  outside  the  cyl- 
inder. Stock  that  will  not 
pass  through  the  screens 
settles  in  drain  E,  from 
whence  it  flows  to  the 
auxiliary  screen.  The  lat- 
ter is  a  specially  designed, 
small,  flat  screen,  where  the 
good  fibers  are  washed 
through  and  recovered. 
The  slots  in  the  revolving  screen  are  cleaned  by  the  shower  pipe 
H.  The  pan  /  serves  as  a  guard  against  splashing,  and  tray  J 
catches  the  water  that  strikes  the  cylinder  and  falls  back.  The 
bodj'  of  the  vat  K  is  made  of  boiler  plate,  and  is  copper  hned;  it 
is  supported  by  two  semicircular  brackets  L,  one  end  of  which 
is,  in  turn,  supported  by  two  vertical  plate  springs  M,  and  the 
other  end  is  supported  by  a  double  pivot  A^  From  this  pivot, 
the  shake  arm  0  extends  to  the  eccentric  P,  which  runs  at  about 
350  r.p.m.  This  vibration  of  the  screen  tends  to  churn  the  stock 
and  urge  the  fibers  through  the  slots. 


Fig.  21. 


32 


PAPER-MAKING  MACHINES 


§6 


37.  Another  type  of  inward-flow  screen  depends  for  agitation 
on  a  difference  of  shape  between  the  rapidly  revolving  drum  and 
the  interior  of  the  vat.  Under  certain  conditions,  this  causes  a 
series  of  varying  suctions  and  pressures  in  the  screen  cylinder, 
which  reproduces,  in  a  measure,  the  action  of  the  diaphragms  in 
the  flat  screen,  A  screen  of  this  type  is  shown  in  Fig.  22,  and  it 
requires  no  eccentric  or  mechanical  vibratory  motion.  The 
agitation  of  the  stock  is  caused  by  the  revolving  of  the  polygonal 
drum  A  at  a  higher  speed  and  in  a  direction  opposite  to  that  of 
the  screen  cylinder  B.     Referring  to  the  diagram,  Fig.  22,  the 

distance  DH  is  less  than  the  dis- 
tances FG  and  EK.  When  drum 
A  revolves  in  the  direction  of  the 
arrow  and  the  point  D  falls  on  a 
radius  drawn  through  E,  the  space 
between  E  and  the  cylinder  will  be 
smaller  than  when  the  drum  is  in 
the  position  shown  in  the  cut,  and 
a  pulsation  outward  will  take  place. 
When  the  point  C  passes  the  point 
on  the  radius  indicated  by  the  point 
"^^°*  ^^"  F,  and  goes  on  to  the  position  of 

the  point  D,  the  space  between  the  drum  and  the  cylinder  becomes 
larger,  and  an  inward  suction  takes  place.  In  other  words,  the 
level  of  the  stock  outside  of  the  drum  is  caused  to  rise  and  fall 
slightly,  provided  the  drum  is  not  entirely  submerged,  which 
creates  a  suction  that  causes  the  stock  to  flow  into  the  drum. 

38.  There  are  several  makes  of  screens  in  which  the  stock  is 
agitated  by  means  of  immersed  plates.  In  one,  a  vertical  plate 
on  either  side  of  the  cylinder  is  moved  by  rods  that  pass  through 
rubber  diaphragms  in  the  side  of  the  vat.  In  another  type,  a 
horizontal  plate  under  the  cylinder,  and  bent  concentric  with  it,  is 
vibrated  up  and  down  by  an  eccentric  having  an  adjustable 
throw.  Still  another  make  has  a  plunger,  with  a  reciprocating 
motion,  in  a  chamber  below  the  screen;  this  creates  suction 
alternately  on  each  end  of  the  screen  cylinder. 

39.  Outward-Flow  Screens. — A  good  example  of  the  outward- 
flow  screen  is  shown  in  Fig.  23 ;  it  is  designed  and  built  for  screen- 
ing high-grade  rag  and  long-fibered  slow  stocks.  The  stock 
enters  the  cylinder  through  pipe  M,  at  one  end;  it  then  drops  to 


§G    THE  PAPER  MACHINE  AND  ITS  EQUIPMENT    33 


the  bottom  of  the  cyHnder,  passes  through  the  slots  into  the 
trough  N,  from  whence  it  goes  to  the  paper  machine.  The 
rejections  are  carried  up  with  the  revolving  cylinder  A,  and  are 
washed  out  through  the  discharge  pan  Q  by  the  shower  V. 
The  shaft  S,  driv^en  by  eccentric  H,  is  fitted  with  a  lever  F  at 
either  end;  it  jerks  the  straps  B,  on  which  rest  circular  projections 
C  of  the  cylinder  A,  which  would  be  journals  if  they  turned  in 

bearings.  This  jerking  of  the  straps 
vibrates  the  cylinder,  and  it  hitches 
it  around  at  the  same  time. 

40.  Another  mechanism,  by 
means  of  which  the  screen  itself  is 
made  to  vibrate,  is  shown  in  Fig. 
24,  where  S  is  the  screen  and  T  is 
the  vat.  The  screen  is  carried  on 
an  arm  A ,  which  is  pivoted  about  a 


Fig.  23. 


point  P;  to  the  other  end  is  attached  a  pawl  C,  which  engages 
with  an  interrupted  cam,  or  ratchet  wheel  W.  As  the  ratchet 
wheel  revolves  in  the  direction  indicated  by  the  arrow,  the  pawl 
is  lifted;  and  this,  in  turn,  lifts  the  arm  and  screen.  When  a 
point  of  the  tooth  is  passed,  the  pawl,  arm,  and  screen  fall;  this 
jars  the  screen,  and  the  jar  loosens  any  fiber  that  may  have 
clogged  in  the  screen.  The  screen  is  revolved  by  a  ratchet  wheel 
that  is  attached  at  one  end  of  the  cylinder. 

41.  A  popular  Enghsh  screen  dithers  (vibrates)  the  cylinder 
by  means  of  an  adjustable,  rotary-eccentric,  center  bearing  at 
one  end.  The  shaft,  which  makes  GOO  r.p.m.,  carries  in  an 
eccentric  position  a  circular  hub  that  turns  in  a  Hoffman  ball 
bearing,  which  is  attached  to  the  spider  that  supports  one  end  of 
the  cylinder. 


34 


PAPER-MAKING  MACHINES 


§6 


42.  Outward-flow  screens  are  thus  seen  to  require  that  the 
screen  cyHnder  be  agitated  to  assist  the  flow;  but  with  inward-flow 
screens,  there  are  also  available  several  other  methods  of  agitat- 
ing the  stock.  An  outward-flow  screen  is  cleaned  by  a  shower 
pipe  outside  the  cyhnder. 

The  principal  differences  in  rotary  screens  lie  in  ruggedness 
and  simplicity  of  design,  difference  in  the  methods  of  creating 
suction  and  agitating  stock,  and  in  the  method  of  removing  the 
rejected  stock. 

A  very  good  discussion  of  screens  is  given  in  the  Section  on 
Treatment  of  Pulp,  Vol.  Ill, 


THE  MODERN  PAPER  MACHINE 


ORIGIN  AND  DEVELOPMENT 

43.  Robert's  Invention. — The  process  of  making  paper  by 
hand,  which  was  the  method  in  universal  use  until  the  invention 
of  the  paper  machine  by  Louis  Robert,  in  France,  in  1799,  is 


Fig.  25. 

described  in  the  Section  on  Handmade  and  Special  Papers,  Vol. 
V.  For  both  handmade  and  machine-made  paper,  the  prepara- 
tion of  the  stock  is  the  same,  and  has  been  fully  explained  in 
previous  Sections. 

The  first  paper-making  machine  that  was  designed  by  Robert, 
see  Fig.  25,  consisted  of  an  endless  wire  cloth  A,  which  passed 
between  two  rolls  B  and  C.  The  position  of  B  was  fixed,  while 
C  was  adjustable,  so  the  wire  could  be  stretched.  The  beaten 
pulp  in  vat  D  was  thrown  up  by  a  revolving  fan  E  against  the 
baffle  plate  F,  which  distributed  the  pulp  and  water  in  an  even 


§6  THE  MODERN  PAPER  MACHINE  35 

stream  on  the  moving  surface  of  the  wire  cloth.  As  the  wire 
cloth  A  traveled  slowly  forward,  the  water  passed  through  the 
wire,  while  the  small  squeeze  rolls  G  completed  the  preliminary 
de-watering.  The  receiving  roll  H  reeled  up  the  wet  sheet  until 
a  sufficient  length  had  been  obtained,  50  feet  being  generally 
accepted  as  the  practical  limit.  The  roll  was  then  removed,  the 
paper  unwound,  passed  through  some  press  rolls,  and  hung  up 
to  dry.  A  working  model  of  this  machine  was  made;  but,  as  is 
always  the  case  with  a  new  design,  it  was  not  perfectly  satis- 
factory. Robert  was  granted  a  bounty  of  8000  francs  to  assist 
him  in  his  studies  and  experiments;  and  he  sold  his  interest  in 
his  patent,  and  his  model  of  the  machine,  to  his  employer,  M. 
Leger  Didot,  of  Essones. 

44.  Early  English  Patents. — M.  Didot  realized  the  greater 
possibility  of  successfully  perfecting  such  a  machine  in  a  country 
free  from  governmental  strife,  and  doubtless  strongly  urged 
thereto  by  his  brother-in-law,  John  Gamble,  an  Englishman, 
he  sailed  for  England  in  the  summer  of  1800.  Didot  had  some 
mechanical  ability,  and  it  is  possible  that  some  improvements  on 
the  original  machine  were  made  by  him  before  leaving  France, 
In  England,  Didot  was  fortunate  in  securing  the  help  of  Mr. 
Bryan  Donkin,  a  man  well  qualified  by  his  mechanical  training 
to  perfect  the  details  of  a  machine  of  this  type. 

45.  On  April  2,  1801,  English  patent  No.  2487  was  granted 
to  John  Gamble  for  the  improved  paper  machine,  the  title  of  the 
patent  being:  "An  invention  for  making  paper  in  single  sheets 
without  seam  or  joining  from  one  to  twelve  feet  and  upwards 
wide,  and  from  one  to  forty-five  feet  and  upwards  in  length." 

Further  improvement  in  design  finally  resulted  in  a  new  patent, 
No.  2708,  dated  June  7,  1803,  issued  by  the  English  govern- 
ment to  John  Gamble  for  "Improvements  and  additions  to  a 
machine  for  making  paper  in  single  sheets  without  seam  or 
joining  from  one  to  twelve  feet  and  upwards  wide  and  from  one 
to  fifty  feet  and  upwards  in  length."     In  the  autumn  of  the  year 

1803,  the  first  paper-making  machine  ever  to  be  built  and  suc- 
cessfully   operated,    was    started    in    Frogmore,    England;    in 

1804,  another  successful  machine,  practically  a  duplicate  of  the 
first,  was  put  into  service  at  Two  Waters,  England. 

46.  In  1804,  Messrs.  Henry  and  Sealy  Fourdrinier  purchased 
the  remaining  interest  of  Didot  and  Gamble  in  the  improved 


36 


PAPER-MAKING  MACHINES 


§6 


Robert  machine.  Henry  Fourdrinier  was  granted  patent  No. 
2951,  on  July  24,  1804,  for  "The  method  of  making  a  machine 
for  manufactming  paper  of  indefinite  length,  laid  and  wove  with 
separate  molds."  On  August  14,  1807,  an  Act  of  the  British 
Parliament  gave  an  extension  of  the  patent  rights  obtained  by  the 
Fourdriniers  for  invention  of  making  paper  by  machinery.  In 
this  Act,  the  machine  described  by  John  Gamble  in  the  specifica- 
tions of  his  patents,  Nos.  2487  and  2708,  together  with  the  added 
improvements,  were  all  fully  described  and  illustrated  by 
diagrams. 

During  the  year  1808,  John  Gamble  assigned  to  Messrs. 
Fourdrinier  all  his  rights  in  the  patents  as  extended  by  this  Act 
of  Parliament,  thus  making  them  the  sole  proprietors  of  the 
patents  covering  the  only  successful  paper-making  machine  in 
existence.  So  the  machine  invented  by  Robert,  promoted  by 
Didot  and  Gamble,  designed  by  Donkin,  and  financed  bj'-  the 
Fourdriniers,  came  to  be  known,  and  continues  to  be  known,  as 
the  Fourdrinier  machine. 

47.  The  Donkin  Machine. — The  fust  Donkin  machine  is 
illustrated  in  Fig.  26.  The  mixture  of  pulp  and  water,  kept  in  a 
state  of  agitation,  flowed  from  the  vat  A,  which  is  like  a  modern 


Fig.  26. 


flow  box,  through  pipes  and  onto  the  endless  wire  cloth  B, 
between  the  endless  deckles  C.  The  wet  sheet  of  paper,  having 
lost  its  excess  of  water,  was  passed  between  the  squeeze  or 
couch  rolls  D,  as  in  the  Robert  machine,  to  be  further  de-watered; 
but,  in  this  case,  the  work  was  better  accomplished  by  reason  of 
the  traveling  upper  felt  E.  This  felt,  the  ancestor  of  the  couch- 
roll  jacket,  also  improved  the  firmness  of  the  wet  paper.  The 
paper  then  traveled  to  the  press  rolls  F  and  G,  and  then  was 
finally  wound  up  on  the  reel  //. 

48.  First     Machines     in    America. — The     first     Fourdrinier 
machine  in  the  United  States  appears  to  have  been  imported  from 


§6  THE  MODERN  PAPER  MACHINE  37 

England,  in  1827,  by  H.  Barclay,  of  Saugerties,  N.  Y.  This 
machine  was  a  Donkin  machine,  60  inches  in  width.  A  second 
Fourdrinier  machine,  62  inches  wide,  was  installed  in  this  mill 
in  1829;  but  the  second  machine  to  be  erected  in  the  United 
States  was  imported  from  England  and  set  up  in  the  Pickering 
Mill,  in  Windham,  Conn.  This  latter  machine  was  copied  by 
Phelps  and  Spafford,  of  Windham,  and  soon  after  that  by  Howe 
and  Goddard,  of  Worcester,  Mass.  The  Fourdrinier  machine 
did  not  come  into  general  use  until  several  years  after  its  first 
successful  operation;  even  in  England,  only  ten  machines  were 
made  between  1803  and  1812,  and  only  twenty-five  more  were 
built  in  the  next  decade.  It  was  not  until  about  1830  that  this 
great  invention  finally  came  into  its  own. 

It  is  noteworthy  that,  in  the  early  daj^s,  the  cylinder  machine 
patented  by  John  Dickinson,  in  1809,  received  more  attention 
from  mechanics  and  inventors  in  the  United  States  than  did 
the  Fourdrinier.  The  supporting  of  the  wire  by  table  rolls  in 
the  Fourdriniers,  and  the  use  of  these  rolls  in  hastening  the 
evacuation  of  the  water,  does  not  seem  to  have  received 
the  attention  these  features  merited;  and,  in  so  far  as  the  writer 
can  find,  no  patents  were  issued  covering  these  points.  In  fact, 
it  is  doubtful  if  many  paper  makers  today  realize  to  an}^  greater 
extent  than  did  the  earlier  generation  the  importance  of  the 
action  of  the  table  rolls. 

49.  Improvements  in  the  Earlier  Machines. — In  1826,  Mr. 
Canson,  in  England,  applied  suction  pumps  to  the  Fourdrinier 
machine,  to  cause  a  suction  underneath  the  wire  on  which  the 
paper  was  formed,  in  order  to  assist  in  the  removal  of  water. 
This  invention  really  was  an  adaptation  from  the  Dickinson 
cylinder  machine. 

It  was  not  until  the  years  1889  and  1890  that  the  modern 
machine  was  perfected,  which,  with  all  its  improvements,  is 
essentially  the  same  machine  as  the  original  of  Fourdrinier  and 
Donkin,  with  the  addition  of  the  cone  drive  and  the  steam-drying 
cyhnders.  Among  the  older  paper  makers,  there  still  lingers 
the  memory  of  when  the  paper  dryers  were  headless  cylinders, 
with  a  wood  fire  in  each  one.  Steam  cyhnders  for  drying  paper 
were  first  used  by  Crompton  in  England,  in  1823. 

The  dandy  roll  was  invented  by  J.  Marshall  in  1826.  In 
1820,  Barrett  invented  a  method  of  making  rolls  true  by  grinding 
them  together,  using  water  and  emery. 


38  PAPER-MAKING  MACHINES 

FOURDRINIER  PART  OF  THE  PAPER  MACHINE 


GENERAL  DESCRIPTION 

50.  General  Data. — A  skeleton  outline  of  the  Fourdrinier 
part  of  a  modern  paper  machine  is  shown  in  Fig.  27.  The  flow 
box,  or  head  box,  1  receives  the  prepared  stock,  which  is  screened 
and  mixed  with  a  large  proportion  of  water.  On  a  slow-speed, 
fine-paper  machine,  the  contents  of  the  flow  box  will  consist  of 
about  1%  of  fiber  and  99%  of  water;  while  in  the  high-speed, 
news  machine,  it  will  consist  of  about  |%  of  fiber  and  99|%  of 
water,  a  ratio  of  water  to  fiber  of  199  to  1,  say  200  to  1.  The 
stock  flows  from  the  flow  box  1  to  the  apron  2,  and  from  thence, 
to  the  wire  3,  which  moves  on  from  the  breast  roll  4  to  the  support 
of  the  table  rolls  5. 

51.  Course  of  the  Wire. — The  wire,  partly  hidden  by  the 
shake  rails,  travels  from  the  breast  roll  4  over  the  table  rolls  5 
and  suction  boxes  6,  under  dandy  roll  7,  over  guide  roll  8,  between 
couch  rolls  9  and  10,  and  comes  back  over  wire  roll  11,  under 
stretch  roll  12,  over  and  under  more  wire  rolls,  and  so  back  to  the 
breast  roll  4.  The  couch  roll  9  is  driven  mechanically;  this,  in 
turn,  drives  the  wire,  which  acts  as  a  belt  and  drives  the  other 
rolls.  The  guide  roll  may  be  outside  and  under  the  wire  near  the 
breast  roll.  The  table  rolls  5  are  supported  by  the  shake  rails  13, 
which  carry  bearings  that  are  so  adjustable  that  the  rolls  just 
touch  the  wire  without  lifting  it.  The  shake  rails  up  to  the  last 
table  roll,  together  with  the  breast  roll  and  several  wire  rolls, 
are  supported  on  the  frames  K,  which  are  pivoted  at  H,  and  are 
raised  or  lowered  at  the  other  end  by  some  device,  such  as  the 
screw-and-worm  gear  W.  Sometimes  the  pivot  is  situated 
beyond  the  suction  boxes.  A  shaft  that  extends  across  the 
machine  connects  the  front  and  back  gears,  which  move  both 
sides  the  same  amount.  The  shake  rail  is  jointed  just  past  the 
last  table  roll,  at  H,  so  the  breast  roll  and  front  part  of  the  wire 
can  be  given  a  jerky,  horizontal  motion,  or  shake,  which  assists 
the  fibers  to  interweave  in  all  directions,  instead  of  flowing 
parallel  to  the  direction  of  the  wire  travel. 

The  rubber  deckle  straps  D,  which  have  a  square  cross  section, 
ride  on  the  wire  and  form  a  tray  for  the  paper  stock,  returning 
over  the  deckle  pulleys  E  and  through  the  wash  trough  F. 


THE  MODERN  PAPER  MACHINE 


39 


Mst. 


While  the  stock  is  being  carried  along 
by  the  wire,  most  of  the  water  passes 
through  it,  under  the  influence  of  gravity 
and  by  the  action  of  the  table  rolls,  and 
flows  into  the  white-water  trays  or  boxes 
B  (sometimes  called  save-alls),  and 
usually  goes  to  the  white- water  pump; 
more  water  is  removed  by  the  suction 
boxes  6,  and  a  little  more  still  by  the 
couch  rolls  9  and  10,  which  also  press 
the  fibers  together. 

52.  Taking  the  Paper  from  Wire  to 
Felt. — The  paper  is  now  sufficiently 
formed  and  firm  enough  to  be  carried 
to  the  first  press  felt.  This  latter  oper- 
ation is  simplified  by  cutting  the  sheet 
into  two  strips,  one  about  1  or  2  inches 
wide,  by  means  of  the  cut  squirt  C, 
which  is  simply  a  nozzle  that  directs  a 
fine  jet  of  water  upon  the  soft  web  of 
paper.  The  reason  for  cutting  the  strip 
is   that   the   machine  tender  can  more 


^^rip     , 


Fig.  28. 

readily  pick  up  this  ribbon  than  he  can 
pick  a  wide  piece  off  the  wire :  he  lays  it 
on  the  first  press  felt;  and  when  this  strip 
is  successfully  carried  onto  the  wet  felt, 
the  cut  squirt  is  pushed  across  the 
machine,  carrying  with  it  its  feeder  hose, 
which  is  supported  in  a  long  slotted  pipe 
that  stretches  across  the  machine,  thus 
cutting  the  paper  all  the  way  across. 
Since  the  paper  is  travehng  toward  the 
couch  rolls  at  the  same  time  that  the  cut 
squirt  is  pushed  across  it,  the  paper  is 


40  PAPER-MAKING  MACHINES  §6 

cut  diagonally,  about  as  indicated  in  Fig.  28.  It  is  evident 
that  if  the  narrow  strip  be  on  the  wet  felt,  the  rest  of  the  paper 
must  also  follow  it  into  place. 

If  the  machine  is  not  equipped  with  a  cut-squirt,  the  paper 
is  placed  on  the  press  felt  thus:  The  machine  tender  pats  the 
edge  from  the  wire,  with  the  palm  of  his  hand  or  with  a  piece 
of  wet  broke,  which  he  slaps  down  so  as  to  create  enough  suction 
to  lift  the  paper.  This  tears  a  narrow  strip,  which  he  widens 
by  lifting  it  skillfully  at  an  angle.  The  back  tender  then  tears 
off  a  bit  of  the  inside  edge  and  pulls  his  part  toward  the  wire 
and  also  toward  the  back  of  the  machine.  This  is  repeated  till  the 
first  narrow  strip  going  to  the  felt  is  widened  to  the  whole  width 
of  the  sheet.  It  is  a  very  delicate  operation,  requiring  skill  and 
patience. 

As  it  leaves  the  lower  couch  roU,  the  return  wire  passes  under 
a  strong  shower,  which  is  situated  over  wire  roU  11.  If  the  paper 
is  not  3^et  ready  to  be  passed  onto  the  wet  felt  from  the  wire,  or 
if  it  be  broken  between  the  couch  rolls  and  wet  felt,  it  wiU  stick 
to  the  wire.  At  roll  11,  all  paper  not  washed  off  will  leave  the 
wire  and  will  stick  to  the  smooth  surface  of  the  roll.  The  doctor, 
or  scraper,  14  scrapes  all  the  paper  off  roll  11,  so  that  it  falls  into 
the  white-water  pit,  or  box,  underneath  the  wire  at  this  point. 
If  lumps  stick  to  this  roll,  they  may  cause  bulges  in  the  wire 
and  produce  much  trouble.  The  wet-paper  broke  collected  in 
this  box,  or  pit,  flows  to  the  save-alls,  to  the  white-water  pump 
suction,  or  to  the  beaters;  in  some  mills,  it  goes  to  waste.  Cir- 
cumstances decide  what  shall  be  done  with  it. 

53.  Up  to  this  point  in  the  description  of  the  Fourdrinier,  no 
mention  has  been  made  of  the  slices,  which  are  situated  near  the 
apron  and  which  control  the  depth  of  the  stock  on  the  wire. 
These,  together  with  the  guard  board  L,  the  stretch  roll  12,  the 
wire  rolls,  the  Fourdrinier  elevating  mechanism  K,  and  the 
save-all,  or  white-water,  boxes  5,  will  all  be  fully  described  later. 
The  dandy  roll  7  (also  shown  in  detail  in  Fig.  41)  rests  lightly 
on  the  wire  where  the  wire  passes  the  first  or  second  suction  box. 

The  pressure  couch  rolls  9  and  10  are  sometimes  replaced  by 
one  suction  roll,  which  is  described  later.  The  wire  is  kept  as 
clean  as  possible  by  continuous  showers  of  fresh  water,  thrown 
on  it  by  the  shower  pipes  S.  Spray  pipes  T  are  placed  over  the 
flow  box  and  apron,  to  break  down  with  fine  sprays  of  fresh 
water  the  froth  that  is  sometimes  formed. 


§6 


THE  MODERN  PAPER  MACHINE 


41 


54.  Right-  and  Left-Hand  Machines. — A  paper  machine  is 
either  a  right-hand  or  a  left-hand  machine.  If  one  stand  at  the 
dry,  or  calender,  end  and  look  toward  the  wet  end,  a  right-hand 
machine  will  have  the  drive  on  the  right  side  of  the  machine, 
while  a  left-hand  machine  will  have  the  drive  on  the  left  side  of 
the  machine.  It  will  be  noticed  that,  on  a  right-hand  machine, 
the  machine  tender  lifts  the  paper  from  the  wire  to  the  first  felt 
with  his  right  hand;  and  uses  his  left  hand  on  a  left-hand  machine. 
The  left  side  of  a  right-hand  machine,  or  the  right  side  of  a  left- 
hand  machine,  is  called  the  front,  or  tending  side. 


DETAILS  OF  THE  FOURDRINIER  PART 


FLOW  BOX  AND  APRON 


55.  The  Flow  Box. — Some  paper  makers  prefer  to  call  this 
part  of  the  machine  the  head  box  or  breast-roll  feed  box,  because 


Fig.  29. 


the  box  at  the  side  of  a  flat  screen  is  also  sometimes  called  a 
flow  box.  Its  purpose  is  to  convert  the  rapid  flow  of  stock  in 
pipe  G,  Fig.  2,  into  a  smooth,  flat  stream  that  will  flow  out  evenly, 
without  eddies,  to* the  [full  width  desired  on  the  wire.  It  also 
provides  a  head  that  will  be  sufficient  to  cause  the  stock  to 
emerge  at  a  speed  that  approaches  that  of  the  wire. 

There  are  many  designs  of  flow  boxes,  the  tendency  being 
toward  simplicity,  as  shown  in  Fig.  29.  Here  the  stock  enters 
at  A,  and  as  it  fills  the  flare  of  the  box,  its  velocity  diminishes. 
The  stock  rises  in  an  even  flow;  it  overflows  at  B,  controlled  by 


42 


PAPER-MAKING  MACHINES 


§6 


the  gate  G,  into  the  white-water  box  W,  Fig.  2,  or  to  waste,  until 
the  machine  tender  is  ready  to  start  the  wire.  An  opening  V 
serves  as  a  washout  for  cleaning. 

56.  Flow  Boxes  with  Baffles. — On  some  machines,  the  flow 
box  has  a  series  of  baffles,  as  shown  in  Fig.  30,  to  eliminate  eddy 
currents.  The  stock  enters  at  A,  passes  up  over  the  first  baffle, 
under  the  second,  and  then  onto  the  apron  D,  through  slot  C. 
The  edges  of  baffles  should  be  rounded.  Outlets  V  are  pro- 
vided at  the  bottom  of  each  division,  which  discharge  to  the  sewer, 
to  the  white-water  tank,  or  to  the  pump  intake;  this  takes  care  of 


Fig.  30. 


the  stock  before  the  wire  is  started,  and  it  prevents  flooding  the 
wire  in  case  of  a  sudden  shut  down.  Parts  G  and  S  are  explained 
later;  they  apply  particularly  to  news  machines. 

57.  A  row  of  holes  or  a  slot  C,  Fig.  3 1 ,  and  (6) ,  Fig.  29,  sometimes 
controlled  by  a  gate,  feeds  the  stock  to  the  machine.  The  space 
between  the  flow  box  and  the  wire  is  bridged  by  an  apron  or  apron 
cloth  E;  this  is  supp:rted  as  far  as  the  breast  roll  F  by  the  apron 
board  D,  which  is  fastened  by  brackets  to  the  front  of  the  flow 
box.  A  part  of  the  box  front,  or  merely  the  board  and  brackets, 
may  be  made  adjustable,  so  as  to  respond  to  any  change  in  the 
inchnation  of  the  wire.  On  some  machines,  the  apron  board,  and 
on  some  the  whole  flow  box,  is  attached  to  the  Fourdrinier  part. 

The  apron  E  may  be  of  oilcloth,  fabrikoid,  or  rubber-coated 
cloth;  it  must  be  thin,  flat,  and  without  wrinkles,  and  it  must  fit 
snugly  to  the  deckle  frame;  it  must  form  a  water-tight  connec- 
tion, and  one  that  will  permit  adjustment  of  deckles  when  the 


§6 


THE  MODERN  PAPER  MACHINE 


43 


width  of  the  sheet  is  to  be  altered.     This  last  is  difficult,  especially 
if  the  Fourdrinier  frame  is  shaken. 

58.  Putting  on  the  Apron. — The  apron  is  put  on  as  follows :  A 
strip  of  dryer  felt  M,  wide  enough  to  reach  from  the  opening  of 
the  flow  box  to  within  about  3  inches  of  the  first  slice  L,  is  so  laid 
down  that  it  reaches  from  edge  to  edge  of  the  apron  board  and 


Fig.  31. 

of  the  wire  W;  on  top  of  this  is  laid  an  apron-cloth  strip  E,  wide 
enough  to  reach  from  the  flow-box  opening  to  within  1  in.  of  the 
slice.  (Some  machine  tenders  bring  the  edge  to  the  slice.) 
Both  felt  and  cloth  are  tacked  to  the  apron  board,  or  are  held  by 
a  strip  of  brass,  screwed  down;  tacks  are  dangerous. 

The  end  of  the  apron  should  not  come  directly  over  a  table 
roll,  since  the  deckle  strap  rides  the  edge  and  will  cause  wear  of 
the  apron  and  make  bad  edges  on  the  paper.  Side  pieces  P, 
of  brass  or  other  suitable  metal,  are  bent  and  fastened  to  the  face 
of  the  flow  box  by  bolts  or  thumb  nuts  /;  there  are  slots  in  the 


44  PAPER-MAKING  MACHINES  §6 

metal  that  permit  side  wise  adjustment.  The  side  pieces  form 
the  sides  of  the  stock-channel  to  the  slices;  they  are  fastened  to 
the  inside  of  the  deckle  frame  H,  on  either  side  of  the  machine, 
just  inside  the  deckle  straps.  The  edges  of  the  apron  E,  on 
each  end,  may  be  carried  up  straight  and  held  tight  against  the 
side  plates  by  a  strip  of  metal  S,  inside  plate  P,  held  in  place  by 
a  clamp  K  at  the  flow  box  and  by  another  clamp  K2  at  the  deckle 
frame  H;  this  clamp  grips  the  side  plate,  apron,  and  inside  plate 
to  the  deckle  frame. 

Sometimes  the  apron  is  allowed  to  stay  flat,  and  the  joint  is 
made  at  each  side  by  a  separate  piece  of  apron  cloth,  about  18 
inches  wide,  which  is  allowed  to  lap  over  on  the  apron;  a  piece  of 
wool  felt  between  the  two  pieces  of  apron  cloth,  sewed  to  the 
upper  one,  helps  to  make  a  tighter  joint.  Sometimes  a  strip 
of  metal  is  laid  flat  on  this  joining  piece,  to  get  a  square  corner; 
this,  however,  is  considered  poor  practice. 

59.  Changing  Width  of  Paper  Sheet. — When  making  only 
a  small  change  in  the  width  of  the  sheet,  the  clamp  on  the  deckle 
frame  is  loosened  until  the  deckle  is  shifted,  the  slack  of  the 
apron  is  taken  up,  or  more  let  out,  and  the  plates  are  again 
clamped  in  place.  For  a  large  change  in  width,  it  may  be  neces- 
sary to  shift  the  connection  at  the  flow  box.  The  flexibility 
of  the  side  plates  provides  for  the  shake  movement. 

60.  New  Design  of  Flow  Box. — There  are  some  new  designs 
of  flow  box,  which  operate  under  a  considerable  head  and  have 
a  spout  that  is  designed  on  hydraulic  principles;  these  boxes 
deliver  a  smooth  current  of  stock  to  the  wire,  without  eddies  or 
ripples,  and  do  not  have  an  apron.  The  most  recent  develop- 
ment is  embodied  in  the  newest  newsprint  mills  in  Canada,  where 
the  front  of  the  flow  box  is  formed  by  the  slice  (see  Art.  72). 
In  Fig.  30,  the  slice  S  forms  the  front  of  a  box,  the  bottom  of 
which  is  the  apron  board  D.  In  place  of  the  apron,  a  brass 
plate  that  forms  the  edge  of  the  apron  board  overhangs  the 
breast  roll  as  far  as  the  top  of  the  roll,  and  is  about  ^  inch  above 
the  wire.  The  edge  of  the  slice,  which  is  sharp,  comes  exactly 
above  the  edge  of  the  plate,  forming  a  standard  orifice }  Wood  or 
metal  grids  G  help  to  eliminate  eddies  and  ripples.  The  deckle 
straps  come  back  against  the  ends  of  this  slice  box,  and  they  arc 
held  close  to  it  by  single-flange  deckle-strap  pulleys  D,  Fig.  32. 

iSce  Part  4  of  Section  1,  Vol  II. 


§6  THE  MODERN  PAPER  MACHINE  45 

A  small  piece  of  rubber  cloth,  extending  about  6  inches  from  the 
slice,  makes  a  square  corner,  and  it  keeps  the  stock  from  leaking 
under  the  deckle  strap  before  the  strap  is  fiat  on  the  wire.  The 
slice  plate  is  adjustable,  to  provide  for  two  widths  of  the  deckle; 
and  the  depth  of  the  stock,  which  is  the  head  in  the  shce  box  or 
pond,  can  be  so  adjusted  as  to  control  the  velocity  of  emergence, 
and  to  make  it  accord  with  the  speed  of  the  wire. 


SOME  TROUBLES  THAT  CAUSE  BREAKS 

61.  Soft  Lumps. — It  is  well  to  note  here  some  of  the  causes 
that  make  the  paper  break,  causes  due  to  conditions  described 
up  to  this  point.  There  are  often  lumps  in  the  stock  as  it  flows  to 
the  machine,  and  these  may  be  either  hard  or  soft.  The  soft 
lump  is  a  new,  thick  blotch  of  stock,  which  has  gradually  accumu- 
lated either  in  the  screen  troughs  to  the  flow  box  or  in  the  flow 
box  itself.  These  lumps  occur  when  there  are  not  a  sufficient 
number  of  water  jets  in  use  to  keep  the  stock  from  settling,  and 
where  fibers  catch  on  splinters,  screw  heads,  etc.  After  a  lump 
becomes  too  heavy,  it  begins  to  flake  in  pieces,  and  passes  from 
its  lodging  place  into  the  hquid.  It  is  then  too  thick  to  disinteg- 
rate again  before  it  reaches  the  wire ;  and  the  result  is  that  when 
it  passes  under  the  dandy  roll  or  between  the  couch  rolls,  the 
extra  thickness  causes  a  crushed  spot  that  breaks  away  from  the 
rest  of  the  sheet,  often  breaking  the  sheet  at  this  point,  or  else 
causing  it  to  break  as  it  passes  through  the  machine.  Soft 
lumps  can  be  prevented  by  removing  splinters,  etc.,  and  by 
using  the  water  hose  occasionally,  thus  washing  the  stock  clean 
from  its  resting  place,  when  the  resting  places  are  known. 

62.  Hard  Lumps. — Hard  lumps  are  dark  in  color;  they  break 
away  from  accumulations  of  stock  that  have  been  gathering  for 
days — sometimes  for  weeks.  These  accumulations  are  found, 
as  a  rule,  between  the  screen  plates  and  the  screen  diaphragms ; 
and  they  may  be  in  the  lower  corners  of  the  stock  trough,  the 
flow  box,  or  even  in  the  apron.  The  remedy  is  to  clean  these 
parts  often  enough  to  prevent  such  accumulations;  this  should 
be  done  at  least  once  every  week. 

63.  Slime  Spots. — Slime  spots  will  often  cause  breaks;  these 
spots  come  from  the  inside  of  the  screens,  from  the  pumps,  and 
from  the  pipes  on  the  entering  side.     Shme  spots  slip  through 


46  PAPER-IMAKING  MACHINES  §6 

the  screen  plates,  when  the  plates  are  old  and  in  poor  condition, 
because  the  slots  are  then  so  large  that  the  slime  passes  readily. 

64.  Thin  and  Heavy  Streaks. — The  paper  breaks  where  there 
are  thin  places  parallel  to  the  edge  of  the  sheet.  These  thin 
places  are  due,  sometimes,  to  the  slice  not  being  evenly  adjusted 
or  to  the  apron  cloth  not  lying  flat,  which  allows  the  stock  to  rush 
onto  the  apron  and  under  the  slices  in  eddying  currents;  this 
causes  flow  on  the  wire  in  several  directions,  and  leaves  heavy 
and  thin  streaks  in  the  finished  sheet  of  paper.  However,  the 
principal  cause  of  these  thin  and  thick  streaks  is  a  poorly  designed 
flow  box  that  allows  eddies  and  cross  currents  in  the  stock  as  it 
flows  to  the  wire.  The  only  cure  for  this  is  so  to  re-design  the 
flow  box  that  the  rush  of  stock  onto  the  wire  may  be  controlled. 
A  perforated  board,  or  grid,  put  in  the  last  section  of  a  flow  box 
divided  into  compartments  by  baffles  that  are  level  with  the  top 
of  the  apron,  will  break  up  these  large  eddies  and  currents  into 
man}'-  smaller  ones,  and  the  stock  can  then  go  onto  the  wire  in  a 
quiet,  uniform  flow.  A  row  of  pins  or  fingers  on  the  apron  board 
may  also  be  used  for  this  purpose,  but  it  is  best  to  avoid 
obstructions.  A  new,  nozzle  type  of  orifice  has  an  adjustable 
flexible  lip  that  works  well. 

65.  Compartments  in  Flow  Box. — Flow  boxes  in  slow'-speed 
machines  frequently  have  but  one  compartment,  as  in  Fig.  29. 
With  medium-speed  machines,  two-compartment  flow  boxes  can 
frequently  be  used.  In  the  case  of  high-speed  machines,  three- 
and  four-compartment  flow  boxes  are  needed,  see  Fig.  30,  because 
the  necessarily  rapid  flow  of  the  liquid  is  harder  to  control. 


THE  DECKLE 

66.  The  Deckle  Frame. — Fig,  32  shows  a  deckle  frame  and  the 
deckle  parts.  The  side  elevation  (6)  shows  how  the  deckle 
frames  F  are  supported  on  the  shake  rails  T  by  the  tubes  L;  it 
also  shows  the  adjusting  screws  S,  which  serve  to  fasten  and  level 
the  frame.  By  turning  the  handle  H,  both  cross  rods  A  are 
turned  simultaneously  by  means  of  the  four  equal  bevel  gears 
(miter  gears)  B.  Each  of  these  cross  rods  is  provided  with  a  long 
screw  thread  on  one  end,  the  screws  traveling  in  nuts  that 
are  fixed  to  the  sleeves  Y .  Spur_ shafts  M  connect  the  bevel 
gears   and   keep   the   deckle  frames  parallel.     When  the   slice 


§6 


THE  MODERN  PAPER  MACHINE 


47 


clamps   are   loosened,   the   turning   of   the   handle  moves  the 
frames  in  or  out,  according  to  the  direction  of  turning.     Each 


deckle  frame  can  be  moved  independently,  which  enables  the 
machine  tender  to  steer  clear  of  a  bad  spot  on  the  wire,  by  moving 


48  PAPER-MAKING  MACHINES  §6 

the  sheet  to  one  side ;  or  he  can  give  more  or  less  trim  on  one  side 
or  the  other,  without  changing  the  shtters,  etc.  The  frames 
carrj'^  sleeves  Y,  which  slide  on  the  tubes  X,  made  in  sections,  the 
outer  section  being  supported  at  the  shake  rails. 

67.  Each  deckle  frame  supports  a  deckle  wash  trough  C.  The 
deckle  strap  K  travels  over  the  supports  P,  and  is  cleaned  by  the 
scrapers  E  on  the  top  and  sides,  as  it  passes,  and  by  streams  of 
water  playing  over  it;  the  water  is  led  awayby  a  pipe  connected  to 
the  outlet  0.  The  deckle  pulleys  D,  next  the  breast  roll,  are  sup- 
ported by  brackets  that  are  fastened  to  the  outside  of  the  frames, 
and  the  apron  side  pieces  are  clamped  to  the  frame  at  this  end. 
The  details  just  mentioned  vary  in  different  makes  of  machines; 
but,  in  general,  they  all  follow  the  type  of  design  here  described. 

Since  the  wire  drags  the  deckle  straps  with  it,  the  passage  of  the 
straps  through  the  wash  troughs  and  over  the  deckle  pulleys 
should  offer  as  little  resistance  as  is  possible.  The  scrapers  E 
should  be  only  close  enough  to  clean  the  strap  without  holding  it, 
and  the  supports  P  should  have  a  smooth  and  easy  curved  surface. 
A  strong  stream  of  water  should  play  on  the  strap  wherever  a  scraper 
acts  on  it.  If  the  strap  be  not  clean,  it  may  cause  a  ragged  edge 
on  the  sheet,  which  may  make  it  stick  to  a  press  roll  and  break  the 
paper. 

68.  Shakeless  Deckle. — If  the  deckle  is  supported  on  the 
Fourdrinier  table  bars  (shake  rails),  it  must  shake  with  the  for- 
ward end  of  the  machine ;  and  when  the  machine  is  large,  the  deckle 
parts  are  heavy  and  cause  considerable  vibration.  For  this 
reason,  shakeless  deckles  have  been  invented,  the  deckle  part 
being  supported  by  columns  from  the  machine  foundation.  How- 
ever, the  shakeless  deckle  cannot  get  away  from  the  deckle  strap, 
which  must  rest  on  the  wire,  and  the  wire  causes  the  straps  to 
shake  and  move  to  and  fro  while  traveling  from  the  table  onto  a 
pulley,  and  when  passing  from  a  pulley  to  the  table.  This  shak- 
ing to  and  fro  of  the  deckle  straps  on  the  wire  near  the  deckle 
pulleys  at  the  apron,  will  give  a  very  uneven  edge  to  the  paper. 
In  the  case  of  a  shakeless  deckle,  this  effect  can  be  overcome  by 
clamping  a  strip  of  metal  to  the  table  bar,  or  to  the  deckle  frame, 
in  such  a  manner  that  it  will  hold  the  inside  edge  of  the  deckle 
strap  down  on  the  wire. 

69.  Deckle  Pulleys. — The  deckle  pulley  should  be  amply 
large;  not  only  because  less  work  is  then  required  from  the  wire 


I 


§6  THE  MODERN  PAPER  MACHINE  49 

but  also  because  the  straps  will  last  longer.  The  following  table, 
issued  by  a  prominent  manufacturer,  gives  the  minimum  diam- 
eters of  deckle  pulleys  for  different  sizes  of  straps,  and  the  pulley 
diameters  should  not  be  less  than  those  here  specified : 

Thickness  of  strap  (inches)  iHflfll    2  2i2| 
Diameter  of  pulley  (inches)  16  18  20  22  24  26  28 

The  second  pulley  is  usually  without  crown,  is  6  or  8  inches  wide, 
of  the  same  diameter  as  the  flanged  pulley,  and  is  attached  to  a 
shaft  extending  across  the  machine  near  the  first  suction  box. 
The  shaft  is  carried  in  brackets  that  are  supported  by  the  table 
bars.  Instead  of  a  single  long  shaft,  very  wide  machines  have  two 
short  shafts.  The  pulle3^s  are  attached  to  the  shaft  by  means 
of  set  screws  or  clamps;  if  these  turn  on  the  shafts,  collars  are 
used  to  keep  the  pulleys  in  position.  An  additional  deckle  strap 
support  may  be  provided  between  the  puUeys  just  mentioned  and 
the  wash  trough. 

70.  The  deckle-strap  pulley  should  never  be  allowed  to  stand 
still  while  the  machine  is  running;  the  deckle  strap  should  run  as 
freelj^  as  possible,  because  the  wire  must  pull  the  strap.  If  the 
pulleys  are  not  turning,  the  strap  is  forced  to  slip  around  them; 
the  friction  between  the  strap  and  the  pulley  then  causes  the 
strap  to  drag,  and  this,  in  turn,  acts  as  a  hold-back  to  the  wire 
itself.  Such  a  condition  of  affairs  causes  the  wire  to  be  strained 
on  the  edges,  and  cracks  quickly  begin  to  show  themselves.  The 
dragging  of  the  strap  on  the  wire  also  prevents  the  formation  of  a 
clean,  even  edge  on  the  sheet  of  paper.  It  is  not  unusual  to  see 
paper  machines  with  deckle  pulleys  of  small  diameter  that  are  not 
even  turning;  the  wires  on  such  machines  wear  out  much  faster 
than  thej^  would  under  better  operating  conditions. 


THE  SLICES 

71.  Purpose  of  the  Slice. — Fig.  33  shows  a  shce  in  plan  and 
elevation;  there  may  be  either  one  or  two  slices  to  a  machine. 
As  the  stock  in  the  flow  box  flows  to  the  wire  between  the  deckles, 
the  thickness  of  the  stream  is  controlled  by  a  cross  piece,  called 
the  slice,  which  is  placed  between  the  deckle  frames,  near  the 
breast  roll.  The  nearer  the  slice  is  to  the  breast  roll  the  better; 
because  the  apron  must  be  extended  up  to  the  slices,  to  insure  con- 
trol of  the  stock,  and  the  greater  the  area  of  wire  that  is  covered  by 


50 


PAPER-MAKING  MACHINES 


§6 


the  apron  the  less  is  the  forming  surface  that  is  available  on  the 
table.     The  stock  that  is  held  back  bj^  the  sHce  is  called  the  pond. 

72.  Slice  Details. — There  are  usually  two  slices,  on  fine-paper 
machines,  about  12  inches  apart,  which  extend  right  across  the 
machine.  The  shce  or  sHces,  as  the  case  may  be,  are  raised  or 
lowered,  so  as  to  control  the  thickness  of  the  stream  of  stock  and 
keep  the  surface  even.  The  height  of  the  slices  with  respect  to 
the  wire  is  adjusted  by  means  of  screws  A^;  and  when  the  proper 
height  is  obtained,  the  lock  nutsL  keep  the  slices  stationary.    The 


cx^rr. 


^      rB 


Fig.  .33. 


brackets  B,  supported  and  moved  by  the  screws  N,  have  tee(T) 
slots,  in  which  tee  sUde  bars  move  up  and  down;  these  tee  slots 
are  riveted  to  the  deckle  frames  A.  The  sHces  are  made  in  two 
parts,  Si  and  S2,  to  allow  of  side  wise  adjustment;  and  they  are 
joined  and  kept  in  Hne  with,  each  other  by  means  of  the  adjusting 
screws  K  and  the  pinch  screws  G.  These  screws  are  held  in 
clamps  C,  carried  at  the  free  end  of  either  shce  bar.  When  the 
deckle  frames  are  moved  in  or  out,  as  described  in  Art.  66,  the 
pinch  screws  are  loosened,  so  the  shces  will  move  with  the  deckle 
frames.  The  pinch  screws  sometimes  pass  through  horizontal 
slots  in  the  shces. 

73.  Position  and  Adjustment  of  Slices. — Care  should  be  taken 
that  the  lower  edge  of  the  sHce  is  kept  straight  and  unbruised;  a 
rough  edge  will  gather  fibers,  which  will  break  away  in  bunches 


§6  THE  MODERN  PAPER  MACHINE  51 

and  give  trouble.  The  lower  edge  must  be  parallel  to  the  surface 
of  the  wire,  to  insure  a  uniform  thickness  of  stock  as  it  flows  onto 
the  wire.  Good  results  are  obtained  by  placing  the  slices  a  little 
back  of  the  center  of,  or  between,  the  table  rolls ;  thej^  should  never 
come  exactly  over  the  center,  since  a  roll  not  in  dynamic  balance  will 
cause  streaks.  The  depth  of  the  stock  behind  the  slice  controls 
the  rate  of  flow  of  stock  to  the  wire ;  this  depth  may  be  as  much 
as  3  feet,  with  the  slice  shown  in  Fig.  30. 

When  the  stock  is  slow  and  carries  (retains)  water  well,  the  slice 
should  be  kept  well  down,  especially  when  making  fine  papers. 
No  more  water  should  be  used  than  is  absolutely  necessary  to 
carry  the  fiber  until  it  has  been  felted  properh^ — the  more  water 
the  more  pumping.  The  level  of  the  stock  behind  the  shce  should 
be  such  that  the  flow  of  stock  will  not  be  slower  than  the  speed  of 
the  wire,  when  it  flows  onto  the  wire.  The  deeper  the  pond  the 
faster,  of  course,  will  be  the  flow  of  stock  onto  the  wire. 


THE  SHAKE 

74.  Purpose  of  the  Shake. — The  breast-roll  end  of  the  wet  part 
is  swaj-ed  to  and  fro  continuously,  which  is  called  the  shake; 
this  agitates  the  pond  behind  the  slices,  and  it  also  agitates  the 
stock  as  it  flows  to  the  wire,  which  causes  the  fibers  to  felt 
together,  as  they  settle  with  and  through  the  water.  The  uniform 
interweaving  thus  obtained  helps  to  make  the  paper  equally 
strong  in  all  directions. 

75.  Amount  of  Shake. — The  vibrating  motion  of  the  breast-roll 
end  of  the  Fourdrinier  wire  is  variable,  the  maximum  movement 
being  about  f  inch  and  the  usual  amount  about  |  inch.  This 
movement  is  caused  by  the  shake  head  and  shake  connecting  rod. 
The  wet  end  of  the  Fourdrinier  is  supported  on  flexible  springs 
on  rocker  arms,  or  is  hung  from  an  overhead  beam,  so  the  breast 
roll  and  wet  end  of  the  wire  can  swing  to  and  fro.  The  shake  head 
on  K,  Fig.  2,  is  a  revolving  disk,  with  an  eccentric  pin,  to  which  one 
end  of  the  shake  connecting  rod  is  clamped;  the  other  end  of  the 
rod,  connected  to  the  breast  roll  supports,  transmits  a  wire- 
vibrating  movement.  The  amount  of  shake  can  be  altered  by 
moving  the  eccentric  pin  nearer  to  or  farther  away  from  the  center 
of  the  shake-head  disk,  to  suit  the  character  of  the  stock;  and  the 
number  of  revolutions  per  minute  of  the  shake  head  can  be  altered 
by  shifting  the  belt  on  cone  pulley  K,  to  which  the  shake  head  is 


52  PAPER-MAKING  MACHINES  §6 

connected.  Many  of  the  new  machines  for  such  papers  as  news- 
print and  the  hke,  are  made  without  any  shake ;  this  permits  more 
substantial  construction,  and  is  one  less  cause  for  worry  to  the 
machine  tender. 

The  interweaving  of  fibers  by  the  shake  is  partly  due  to  care- 
fully adjusting  the  speed  of  the  stock  to  the  speed  of  the  wire. 
The  most  carefully  felted  sheets  are  secured  when  the  fibers 
settle  by  gravity  as  the  water  drains  away;  the  fibers  then  fall 
naturally  and  evenly  in  all  directions,  and  there  is  no  "dragging 
the  feet  from  under  them,"  as  it  were.  The  effect  of  the  shake 
is  to  knock  the  fibers  down  crosswise,  while  the  forward  travel 
of  the  wire  pulls  them  down  lengthwise  of  the  sheet.  The 
shake  can  be  varied  from  a  long,  slow  motion  to  a  short,  jerky 
motion;  as  a  rule,  the  more  violent  the  shake  the  better  the 
paper. 

FOURDRINIER  ROLLS 

76.  Kind  of  Rolls. — Before  describing  the  Fourdrinier  rolls, 
attention  is  called  to  what  a  roll  is  and  to  its  uses.  There  are 
many  rolls  across  a  paper  machine,  and  they  are  made  of  various 
materials,  as  wood,  bronze,  steel,  cast  iron,  and  even  stone. 
They  all  tend  to  sag  in  the  middle  because  of  their  weight,  even 
without  carrying  any  load  on  them.  In  addition  to  their  own 
weight,  the  table  rolls  support  a  part  of  the  weight  of  the  wire 
and  a  part  of  the  weight  of  the  stock  from  deckle  to  deckle. 
Press-felt  rolls  are  subjected  to  the  pull  of  the  felts;  sometimes 
there  is  half  a  lap  of  felt  on  a  roll  and  a  double  pull,  while  some- 
times there  is  very  little  lap  and  a  consequently  small  pull; 
sometimes  the  direction  of  the  pull  is  upwards  and  sometimes  it 
is  downwards.  The  dryer-felt  rolls  have  felts  pulling  upwards 
or  downwards  on  them.  The  lower-press  rolls  have  upper-press 
rolls  on  top  of  them,  and  these  upper-press  rolls  have  levers  and 
weights  on  their  journals,  which  increase  the  pressure  of  the 
upper-press  roll  upon  the  lower  roll.  In  order  that  the  machine 
may  make  a  uniform  sheet  of  paper,  it  is  advisable  that  the  top 
of  a  bottom  roll  be  always  straight  as  it  turns  over;  similarly, 
the  upper  rolls  should  be  straight  across  the  bottom  rolls. 

77.  Crown  of  Rolls. — In  order  to  keep  the  sheet  of  paper 
uniform,  it  is  necessary  to  crown  a  single  roll,  or  the  lower  roll  of 
a  pair,  by  making  its  diameter  in  the  middle  just  enough  larger 


§6  THE  MODERN  PAPER  MACHINE  53 

than  at  the  ends  to  make  up  for  the  sag  in  the  middle  that  is 
caused  by  the  weight  the  roll  carries  when  in  the  machine;  the 
crown  is  measured  in  thousandths  of  an  inch. 

78.  The  Breast  Roll.— The  breast  roll  4,  Fig.  27,  should  not  be 
crowned;  because  the  wire  wraps  around  a  large  part  of  its 
circumference,  and  if  the  roll  were  crowned,  the  wire  will  be 
stretched  in  the  middle  more  than  at  the  ends,  thus  making  the 
center  of  the  wire  travel  ahead;  this  would  not  only  shorten  the 
life  of  the  wire  but  it  would  also  tend  to  give  an  uneven  surface 
on  the  table. 

79.  Breast  Roll  Details. — The  fact  that  the  breast  roll  is 
driven  by  the  wire  makes  it  necessary,  in  order  to  lengthen  the 
life  of  the  expensive  wires,  that  this  roll  should  turn  easily.  It 
should  be  as  light  as  possible;  it  should  also  be  fairly  large  in 
diameter,  so  the  wire  may  turn  it  more  easily,  and  thus  reduce  the 
strain  on  the  wire  that  is  due  to  bending  the  wire  around  the  roll. 
For  a  roll  to  revolve  easily,  it  should  be  m  balance;  it  should  be  as 
light  as  possible,  yet  stiff  enough  to  keep  its  shape;  lastly,  the 
journals  should  be  well  lubricated.  In  more  modern  machines 
of  a  large  size,  the  advisability  of  using  ball  or  roller  bearings 
on  some  rolls  of  the  paper  machine,  to  reduce  the  strain  on  the 
clothing,^  has  become  more  generally  recognized. 

Attempts  to  drive  the  breast  roll  independently  have  not 
been  successful,  because  of  the  practical  difficulty  encount- 
ered in  so  driving  the  roll  that  its  peripheral  speed  will 
exactly  equal  the  speed  of  the  wire,  which  is  driven  by  the  lower 
couch  roll. 

Fig.  27  shows  the  breast  roll  in  place,  with  the  doctor  as 
usually  hung;  the  doctor  scrapes  off  the  pulp  and  keeps  it  from 
passing  around  with  the  roll,  under  the  wire,  and  so  stretching 
the  wire  and  making  bulges  in  it.  For  reasons  previously 
stated,  all  breast  rolls  are  ground  straight,  i.e.,  without  any 
crown. 

This  roll  is  on  the  wet  part  of  the  machine,  and  should 
therefore  be  made  of  non-corrosive  metal;  it  is  also  in  position 
to  pick  up  much  fiber,  and  should  therefore  have  a  doctor  to 
keep  it  clean.  A  similar  line  of  reasoning  may  be  applied  to  the 
other  rolls  of  the  machine. 

1  Clothing  is  the  name  given  to  the  combination  of  wire,  jacket,  wet 
felts  and  dryer  felts. 


54 


PAPER-MAKING  MACHINES 


§G 


Fig.  34  shows  a  section  of  a  breast  roll ;  and  it  will  be  seen  that 
every  effort  has  been  made  to  produce  a  breast  roll  that  will  be 
as   light   as  possible.     The  extension  with  the  brass  sleeve  is 


Fig.  34. 

provided  for  the  purpose  of  slipping  the  end  of  a  porter  bar  or 
lifting  lever  (see  Fig.  35)  over  the  end  of  the  journal,  as  the 
breast  roll  is  being  lifted  out  of  the  machine  when  changing  wires. 

To  fit  couch  journal  or  breast  roll  journal 
Hard  wood  filler 


k'^^A^i.-::.-.-  ^■;»t»^i^^^^N^»»^:^y!^t»»^»;^^^^yA;J^.»^■tJ^^^ 


SN^^S^^'^ 


^^ 


■s-  vy^^-y.-':^':;;^::;^ 


XX   Heavy  pipe 

Fig.  35. 


Eye  for  chain  hoist 


80.  Table  Rolls. — Fig.  36  shows  a  roll  that  consists  of  a  steel 
tube,  cast-iron  heads,  and  steel  journals;  this  type  of  roll,  covered 
with  a  brass  tube  or  casing,  is  a  standard  design  of  Fourdrinier 


Fig.  36. 

roll.     The  illustration  shows  the  general  construction  of  stretch, 
guide,  and  wire  rolls. 

The  table  rolls  must  be  as  light  as  possible,  consistent  with  the 
securing  of  the  necessary  stiffness.  They  are  made  from  a  brass 
tube  T,  and  have  a  cast-iron  or  brass  head  //,  which  carries  the 
steel  journal  J.  The  journals  rest  in  adjustable  bearings  that  are 
supported  by  the  shake  rails,  either  on  the  rails  or  under  them. 


§6  THE  MODERN  PAPER  MACHINE  55 

81.  Size  of  Table  Rolls. — Fourdrinier  rolls  will  soon  deteriorate 
if  acid  stock  (which  arises  from  alum  or  antichlor)  is  used.  The 
acid  soon  attacks  the  zinc  in  the  brass  covering;  and,  in  course 
of  time,  it  leaves  only  a  rotten,  porous,  copper  shell,  which  will 
readily  break.  This  action  occurs  in  connection  with  all  brass 
parts.  The  table  rolls  have  the  smallest  diameter  of  any  of  the 
Fourdrinier  rolls,  varying  from  2  inches  in  diameter  on  small  mach- 
ines to  6  inches  or  larger  on  the  very  wide  machines.  Machine 
designers  now  recognize  the  advantage  of  large  rolls. 

82.  Care  of  Table  RollSv— Care  should  be  taken  to  keep  the 
table  rolls  turning;  if  a  roll  be  allowed  to  stop  turning  (become 
dead),  it  wears  the  wire,  and  the  roll  itself  wears  flat  where  the 
wire  passes  over  it.  When  a  roll  having  a  flat  spot  on  it  turns, 
it  bumps  the  wire  and  makes  ridges  in  the  paper.  If  a  roll  will 
not  keep  turning  after  proper  lubrication  and  adjustment,  it 
should  either  be  replaced  with  a  new  roll  or,  if  only  slightly  worn, 
the  journals  and  bearings  should  be  inspected  and  corrected. 

In  addition  to  reducing  the  friction  between  the  table  roll  and 
the  wire,  there  is  another  reason  why  the  table  rolls  must  turn; 
the  moving  surface  brings  the  water  out  of  the  paper  more  easily, 
which  does  not  occur  w'hen  the  rolls  are  not  turning. 

83.  Effects  Produced  by  Table  Rolls.— Because  of  the  wearing 
effect  produced  by  the  friction  between  the  rolls  and  the  wire, 
some  machines  have  been  equipped  with  a  light  belt  drive  on 


Fig.  37. 

these  rolls;  this  eliminates  dead  rolls.  Dead  rolls  may  also  be 
avoided  by  using  ball  bearings.  In  order  that  the  rolls  may  turn, 
it  is  necessar}',  of  course,  that  the  rolls  be  in  contact  with  the  wire. 
The  diagram.  Fig.  37,  illustrates  how  the  swiftly  turning  rolls 
on  high-speed  machines  tend  to  throw  water  back  under  the  wire. 
The  rolls  have  much  the  same  effect  in  inducing  water  to  leave  the 
under  side  of  the  wire  as  is  produced  by  touching  the  inside  of  a 
wet  tent  or  a  string  of  rain  drops.  An  English  writer^  explains 
the  action  of  the  table  rolls  by  assuming  that  a  slight  vacuum 
^  Chalmers,  in  Paper  Making  and  Its  Mnchinenj,  1920,  p.  78. 


56  PAPER-MAKING  MACHINES  §6 

tends  to  form  in  front  of  the  roll.  A  film  of  water  may  follow 
the  roll  to  the  wh'e  and  flow  down  the  back  side  of  the  roll. 

A  discussion  of  the  dynamics  of  rolls  is  given  in  Art.  214. 

84.  Efifects  of  Water  and  Its  Removal. — It  is  necessary  to  have 
sufficient  water  in  the  stock  to  keep  the  fibers  in  suspension  for  a 
considerable  distance  on  the  wire;  this  affords  time  for  the  fibers 
to  interweave  properly  and  to  produce  a  well-formed  sheet. 
Since  water  drains  rapidly  from  a  free  stock,  such  as  is  used  for 
coarse  papers,  more  water  is  used  to  produce  this  degree  of 
suspension.  High-grade  papers  are  inade  from  slow  stock,  and 
the  amount  of  water  required  is  less  in  this  case.  Most  of  this 
water  is  removed  as  the  paper  passes  the  table  rolls,  and  it  is 
here  that  the  paper  is  formed. 

The  forming  table  and  the  suction  boxes  must  take  out  enough 
water  to  keep  the  paper  from  being  crushed  at  the  couch  press, 
which  is  the  effect  produced  when  the  water  is  pushed  out 
unevenly,  leaving  the  fiber  in  blotches.  With  stock  of  the  same 
freeness,  the  more  table  rolls  the  faster  the  machine  can  be  run. 
If  the  paper  be  too  wet  at  the  first  suction  box,  the  machine 
should  be  slowed  down,  less  white  water  should  be  added  at  the 
regulating  box,  or  the  stock  should  be  made  more  free.  To  make 
the  stock  more  free,  warm  the  stock  as  it  comes  to  the  machine, 
or,  better,  change  the  treatment  in  the  beater;  heating  costs 
money.  If  the  forming  table  takes  out  the  water  too  quickly, 
the  instructions  just  given  may  be  reversed,  or  several  of  the 
roll  bearings  may  be  lowered  until  these  rolls  are  out  of  action, 
out  of  contact  with  the  wire.  Adjacent  rolls  should  not  be 
lowered  nor  those  toward  the  suction  boxes. 

When  making  tissue  papers,  the  table  rolls  should  be  close 
enough  together  to  keep  the  water  that  has  been  removed  from 
being  thrown  back  against  the  under  side  of  the  paper;  a  thin 
paper,  such  as  cigarette  paper,  will  be  spoiled  if  drops  are  thrown 
against  the  under  side  of  the  wire.  When  starting  a  fast  machine 
on  coarse  paper,  it  is  well  to  begin  with  plenty  of  water,  cutting 
it  down  if  necessary;  the  opposite  procedure  should  be  followed 
in  the  case  of  a  slow  machine  on  fine  papers. 


SUCTION  BOXES 


85.  Purpose  and  Description. — The  suction  boxes  must  take 
out  sufficient  water  to  keep  the  paper  from  being  crushed  under 


§6 


THE  MODERN  PAPER  MACHINE 


57 


the  couch  press.  The  usual  design  of  a  suction  box 
is  shown  in  Fig.  38.  The  box  is  made  of  bronze,  and 
its  interior  is  rectangular  in  shape.  The  bottom  of 
the  box  is  connected  to  the  suction  pump  by  means 
of  a  pipe  3;  in  some  designs  there  are  as  many  as 
six  outlets  from  the  box  to  this  pipe.  The  rubber 
pistons  1  are  pushed  in  or  are  pulled  out  by  means 
of  the  handles  2,  the  ends  of  which  fit  into  slots 
in  the  pistons  and  lock  them  in  position.  The 
pistons  are  set  just  under  the  edge  of  the  paper,  to 
keep  air  from  entering  the  box.  On  the  top  of  the 
box  rests  a  perforated  cover  4,  made  of  hardwood — 
maple  or  mahogany — or,  sometimes,  of  hard  rub- 
ber or  brass;  maple  is  preferable  for  suction  boxes, 
since  it  can  be  easily  planed  and  kept  smooth; 
and  the  cover  must  be  kept  smooth,  to  reduce  the 
friction  as  the  wire  passes  over  it.  The  wire  wears 
ridges  or  grooves  in  the  covers,  which  soon  destroy 
the  m£sh  or  cause  the  wire  to  wrinkle  and  produce 
defects  in  the  paper;  the  covers  should,  therefore, 
be  planed  smooth  every  week  end.  If  the  stock 
be  coarse  and  but  little  suction  required,  it  is  bad 
practice  to  close  one  box  entirely;  it  is  better  to 
decrease  the  suction  on  all  the  boxes,  by  slightly 
closing  the  valves  on  the  vacuum  pump  suction. 

From  4  to  9  boxes  are  used,  according  to  the 
kind  of  paper,  speed  of  the  machine,  and  the 
amount  of  water  left  in  the  stock  after  passing  the 
table  rolls.  Some  machines  are  equipped  with  a 
device  for  giving  a  reciprocating  motion  to  one  end 
or  both  ends  of  the  suction  boxes  (all  connected 
together),  so  as  to  minimize  the  scoring  of  the  box 
tops.  A  great  deal  of  work  has  recently  been  done 
on  the  subject  of  suction  boxes,  and  successful  new 
designs  will  doubtless  soon  be  in  use. 

86.  Amount  of  Vacuum. — A  vacuum  gauge  should 
be  placed  on  the  suction-pump  line  from  the  suction 
boxes,  so  the  machine  tender  can  be  guided  in  his 
control  of  the  suction.  From  7  to  10  inches  of 
mercury  (vacuum)  is  ample  for  the  suction;  and  if 
the  work  of  the  boxes  is  not  satisfactory  when^over  7 


^y." 


-^ 


^si 


I 


58 


PAPER-MAKING  MACHINES 


§G 


inches  of  vacuum  is  shown  on  the  gauge,  it  is  better  to  place  an 
additional  box  under  the  wire  than  to  strain  the  wire  too  much  by 
increasing  the  vacuum  to  above  10  inches.  It  is  not  unusual  to  see 
14  inches  of  vacuum  on  suction  boxes;  but  this  is  bad  practice,  as 
the  wires  are  then  soon  worn  out.  The  suction  pulls  the  wires  down 
onto  the  top  of  the  boxes  and  tends  to  make  the  wire  drag,  like  a 

brake.  A  vacuum  of  7 
inches  on  a  100-inch  ma- 
chine is  equivalent  to  a  load 
of  about  1000  pounds  for 
each  box;  this  not  only- 
increases  the  pull  required 
to  drag  the  wire  off  the 
boxes  but  it  also  causes  a 
suck  in  and  release  as  the 
wire  passes,  which  strains 
the  mesh.  In  a  patented 
arrangement,  this  effect  is 
minimized  by  placing  the 
boxes  contiguous.  As  pre- 
viousl}"  stated,  these  strains 
on  the  wire  should  be  made 
as  small  as  possible,  so  as 
to  save  the  wires  and  make 
good  paper. 

87.  Suction  Pumps, — 
The  suction  pump  is  often 
similar  in  design  to  the  stuff 
pump,  but  the  valves  must 
act  quickl}'.  Fig.  39  shows 
a  section  of  one  c^dinder 
of  a  suction  pump,  which 
may  have  two  or  three  cylind(>rs.  The  suction-pipe  connection 
S  is  connected  to  the  pipe  3,  Fig.  38,  of  the  suction  boxes. 
Between  it  and  the  pump  is  a  separator  for  taking  out  the  air  that 
is  drawn  through  the  paper  as  the  water  is  removed.  This 
water  contains  recoverable  fiber.  The  discharge  pipe  D  delivers 
the  water  and  fiber,  sucked  from  the  suction  boxes,  into  save- 
alls  or  to  the  sewer.  The  action  of  the  disk  springs,  as  the 
plunger  moves,  is  the  same  as  that  of  the  ball  valves  of  the  stuff 
pump  shown  in  Fig.  5;  the  spring  insures  quick  and  positive 


Fici.  39. 


§6  THE  MODERN  PAPER  MACHINE  59 

closing,    with   minimum   leakage.     In   Fig.    39,    the   plunger  P 

has  just  finished  a  down  stroke;  the  air  in  the  pump  has  been 

expelled  through  Z),  and  the  lower  valve  is  about  to  open,  as  the 

up  stroke  of  P  admits  air  through  S.     The  cushioning  effect  of 

the  air  is  so  materially  reduced  by  the  vacuum  created  that  the 

seating  of  a  valve  is  much  more  sudden  than  it  would  be  if  it 

were  moving  in  the  atmosphere;  this  necessitates  moving  parts 

of  special  design.     Rubber  is  generally  used  in  the  manufacture 

of  the  suction  and  discharge  valves;  but  experience  has  shown 

that  rubber-ball  valves  are  not  as  good  as  rubber  disks,  with 

controlling  springs. 

88.  Displacement  of  Suction  Pumps. — The  displacement  of  the 

suction  pump  should  approximate  500  cu.  in.  per  inch  of  width 

of  wire  and  for  each  100  feet  of  paper  made  per  minute.     Hence, 

for  a  width  of  130  in.  and  a  speed  of  450  ft.  per  min.,  the  dis- 

450 
placement  under  these  conditions  should  be  500  X  130  X  ^ru) 

=  292,500  cu.  in.  per  min.  However,  this  amount  is  possibly 
excessive,  if  applied  to  high-speed  news-machine  problems,  when 
the  speed  is  over  600  ft.  per  min. ;  the  paper  then  loses  its  moisture, 
and  the  work  required  of  the  pump  is  less  in  the  last  suction 
boxes  than  in  the  first  boxes.  While  the  paper  machines  may 
have  a  varying  number  of  suction  boxes  for  the  same  speed,  the 
greater  part  of  the  work  done  by  the  pumps  is  in  the  first  two  or 
three  boxes;  therefore,  the  same  displacement  of  pump  will,  as  a 
rule,  take  care  of  an  extra  suction  box,  if  the  displacement  be 
calculated  according  to  the  above  rule.  The  character  of  the 
stock  governs  to  a  certain  extent  the  amount  of  suction  require  d ; 
for  instance,  groundwood  is  slower  stock  than  sulphite,  and  thus 
requires  a  higher  vacuum  to  suck  the  water  out.  But  when  the 
stock  is  slow,  the  machine  is  usually  slowed  down. 

On  a  suction  couch  roll,  a  higher  vacuum  is  necessary  in  order 
to  do  efficient  work;  this  is  also  true  of  the  wet-press  suction  boxes. 
The  size  of  the  pump  for  press  suction  boxes  can  be  taken  care  of 
by  allowing  275  cu.  in.  displacement  of  suction  pump  per  minute 
per  inch  of  width  of  press  roll.  In  order  to  exert  a  continuous 
suction  on  the  wire  or  press  felt,  the  smallest  capacity  of  pump 
that  is  practicable  is  6"  X  8",  that  is,  6  in.  in  diameter  by  8  in. 
stroke. 

Other  types  of  exhausters,  especially  centrifugal  pumps,  are 
also  used  on  suction  boxes  instead  of  the  displacement  pumps 


60 


PAPER-MAKING  MACHINES 


§6 


0? 


3J 


here  described;  these  other  designs 
are  at  least  equally  efficient.  A 
special  treatment  of  the  subject  of 
pumps  is  included  in  Vol.  V,  in  the 
Section  on  General  Mill  Equipment. 


GUIDING  THE  WIRE 

89.  The  Guide  Rolls.— The  guide 
roll  8,  Fig.  27,  is  provided  with  a 
wire  guide  on  the  front  side  of  the 
machine.  A  design  of  wire  guide, 
as  attached  to  the  guide  roll  on  a 
left-hand  machine,  is  illustrated  in 
Fig.  40.  The  guide  acts  by  shifting 
the  position  of  the  bearings,  carry- 
ing the  front  end  of  the  roll  for- 
wards or  backwards  as  the  wire  gets 
out  of  line. 

90.  The  Palms.  — Referring  to 
Fig.  40,  two  palms,  or  fenders,  Pi 
and  Pi,  are  fixed  on  a  wooden  rod 
A ,  which  crosses  the  machine  under 
the  wire  in  such  a  manner  that  the 
edges  of  the  wire  just  clear  the 
palms.  Now  consider  what  hap- 
pens when  the  wire  travels  to  the 
front  side^  and  pushes  against  palm 
Pi.  This  action  moves  the  wooden 
rod  A  to  the  front  of  the  machine, 
carrying  with  it  link  M,  which  is 
firmly  keyed  to  rod  A;  and  this, 
in  turn,  moves  bell-crank  levers 
N    and    0.     The    latter    revolves 

^The  front  side  of  the  machine  is  the 
tending  side,  the  side  opposite  the  one  on 
which  the  drive  is  located,  which  is  called 
the  back  side.  Hence,  on  a  left-hand 
machine,  the  front  side  will  be  on  the 
right,  when  looking  toward  the  wet  end 
(see  Art.  54). 


§6  THE  MODERN  PAPER  MACHINE  61 

around  the  center  pin  Q,  which  is  carried  by  bracket  B.  One 
end  of  lever  0  is  connected  to  rod  C,  which,  as  the  front  palm 
comes  forward,  pulls  the  double  pawl  L  and  R,  so  that  pawl  R 
locks  into  the  rachet  wheel  W.  Since  the  double  pawl  is  hung 
on  the  eccentric  E,  it  moves  up  and  down  once  with  every  revolu- 
tion of  the  guide  roll,  and  it  is  constrained  to  move  vertically. 
When,  as  in  this  case,  the  rod  C  pulls  pawl  R,  which  is  in  gear 
with  the  wheel,  the  pawl  pushes  down  on  the  wheel,  turns  it 
around,  and  causes  it  to  travel  to  the  right  on  screw  K,  toward 
the  direction  in  which  the  wire  is  travehng.  Since  the  ratchet 
wheel  carries  the  front  bearing  D  of  the  guide  roll,  the  result  of 
the  above  described  movements  is  to  screw  the  front  side  of  the 
guide  roll  forwards  by  means  of  its  own  revolutions,  thus  causing 
the  wire  to  be  forced  by  the  guide  roll  to  travel  back  again  to 
its  normal  position. 

If  the  wire  tend  to  travel  toward  the  back,  or  driving,  side  of 
the  machine,  the  movements  above  described  are  reversed;  pawl 
L  then  locks  into  the  ratchet  wheel,  lifts  on  the  ratchet  wheel,  and 
causes  it  to  travel  to  the  left.  The  new  position  of  the  roll  causes 
the  wire  to  retrace  its  path  toward  the  front  of  the  machine. 

There  are  other  types  of  wire  guides,  but  they  all  work  on  the 
same  general  principle — that  of  shifting  the  front  bearing  of  the 
guide  roll.  A  widely  used  tj^pe  has  but  one  palm,  held  against 
the  wire  b}-  a  spring;  it  is  especially  adapted  to  wide  machines. 
A  new  type  has  no  palm;  a  water  jet  which  strikes  a  spoon 
lever  if  the  wire  moves  either  way,  actuating  the  gear. 


THE  DANDY  ROLL 

91.  The  Watermark. — When  it  is  desired  to  make  a  water- 
mark (a  name  or  design)  on  the  paper,  it  is  effected  by  using  a 
dandy  roll.  A  dandy  roll  is  a  skeleton  roll,  covered  with  wire 
cloth,  upon  which  the  design  is  worked  in  fine  wire,  though  brass 
letters  are  sometimes  used.  This  raised  design  makes  the  soft 
paper  thinner  where  it  comes  in  contact  with  the  design,  and  the 
outline  shows  clearly  when  the  paper  is  held  between  the  eye  and 
the  light. 

92.  Wove  and  Laid  Papers. — If  the  paper  is  to  be  alike  on 
both  sides  and  without  a  watermark,  the  dandy  roll  is  covered 
with  fine  wire,  similar  in  texture  to  the  machine  wire.  This 
dandy  roU  produces  what  is  called  wove  paper;  because  the  wire 
impressions  are  similar  on  both  sides,  and  the  paper  has  the  appear- 


62 


PAPER-MAKING  MACHINES 


§6 


ance  of  being  woven.     A  dandy  roll  that  has  a  series  of  wires  on  its 

surface,  the  wires  being  so  arranged  as  to  produce  parallel  hnes 
on  the  paper,  these  lines  being  more  transparent  than  the  rest  of 
the  paper,  produces  what  is  called  laid  paper. 

93.  Size  and  Position  of  Dandy  Rolls. — The  diameter  of  a 
dandy  roll  varies  from  7  to  2-4  inches,  depending  on  the  width  and 
speed  of  the  machine,  the  design  of  the  watermark,  and  the  kind 
of  stock;  it  is  placed  on  the  wire  and  between  the  suction  boxes, 
see  7,  Fig.  27.  The  roll  rests  on  the  wire,  and  its  journals  revolve 
in  guides  rather  than  in  bearings.  The  roll  is  turned  by  the 
friction  between  it  and  the  paper.  As  this  roll  runs  on  the  surface 
of  the  paper,  it  presses  out  some  water,  and  it  gives  the  paper  a 
closer  and  finer  finish,  which  is  its  primary  function. 


Fig.  41. 


The  circumference  of  a  dandy  roll  is  usually  a  little  less  than 
the  distance  (lengthwise)  desired  between  the  watermarks  on  the 
dried  sheet;  this  allows  for  stretch.  The  distance  crosswise 
between  the  designs  is  a  little  greater  than  is  desired  in  the  dried 
sheet;  this  allows  for  shrinkage.  Dandy  rolls  for  loft-dried 
papers  should  have  a  greater  width  between  designs,  because  of 
the  greater  shrinkage  in  high-grade  papers. 

94.  Fig.  41  shows  a  design  of  dand3-roll  stand,  and  by  referring 
to  Fig.  27,  the  usual  position  of  the  dandy  roll  will  be  noted;  it  is 
generally  placed  after  the  first  set  of  suction  boxes,  but  not  directly 
over  a  roll.  Fig.  41  shows  the  adjusting  screws  S,  with  a  thumb 
head,  and  wing  nut  W,  for  adjusting  the  height  of  the  dandy-roll 
guides  B  to  accord  with  the  size  of  the  dand}'  roll  D.  Lever  A  is 
so  linked  to  the  dandj^-roll  guides  or  bearings  that  an  upward 
movement  of  the  lever  will  immediately  hft  the  dandy  roll  from 
the  surface  of  the  paper,  if,  for  any  reason,  it  is  necessary  to  do 


§6  THE  MODERN  PAPER  MACHINE  G3 

so.     When  not  in  use,  as  when  starting  the  machine,  the  dandy- 
roll  may  be  hung  in  bracket  H . 

When  the  dandy  roll  makes  proper  contact  with  the  paper,  a  wet 
streak  of  even  width  shows  just  behind  the  roll.  Experience  is 
required  to  get  the  right  amount  of  wetness  to  the  paper,  so  the 
dandy  roll  will  make  the  right  impression.  This  is  done  by  con- 
trolling the  suction  and  by  proper  beating  of  the  stock.  The 
paper  in  this  book  is  made  with  a  wove  dandy.  A  surface  mark  is 
obtained  on  some  machines  by  printing  the  letters  on  the  paper  as 
it  passes  over  one  of  the  hard  rolls  of  the  press  part. 

95.  Defects  Caused  by  Dandy  Rolls. — Dandy  marks  some- 
times cause  defective  paper  and  breaks.  The  wire  cloth  that 
covers  the  skeleton  drum  may  become  plugged  in  the  meshes  with 
fine  particles  of  stock  and  filler;  and  when  this  occurs,  the  water  on 
top  of  the  sheet  cannot  penetrate  through  the  plugged  meshes. 
As  a  consequence,  the  sheet  at  these  points  tends  to  stick  to  the 
face  of  the  dandy  roll,  and  it  is  slightly  lifted  by  the  roll.  This 
action  causes  a  mark  on  the  sheet  that  has  somewhat  the  shape 
of  a  half  moon,  and  there  is  only  one  remedy  for  it:  the  dandy  roll 
must  be  taken  from  the  machine  and  thoroughlj'  washed  out  with 
water  and  steam.  When  the  meshes  are  badly  plugged,  and  the 
plugs  are  dried  into  the  wire  cloth,  it  may  be  necessary  to  use  a 
steam  hose.  In  some  cases,  dilute  oil  of  vitriol  (sulphuric  acid), 
lightly  applied  with  a  cloth,  is  necessary  to  clear  the  dandy  roll 
of  these  obstructions,  and  some  mills  keep  steam  or  air  jets  blow- 
ing through  the  dandy  on  the  machine.  A  piece  of  wet  felt,  tacked 
to  a  bar,  may  be  hung  the  length  of  the  dandy  for  use  as  a  wiper. 

Unless  very  carefully  cleaned  at  the  end  of  a  run,  some  paper 
stock  will  adhere  to  the  wire,  and  the  acid  treatment  will  be 
required  when  the  dandy  is  next  used.  The  acid  wash  is  prepared 
by  pouring  sulphuric  acid  into  a  pail  of  water  until  a  distinct  acid 
taste  is  noticed,  about  like  lemon  juice.  The  roll  is  placed  on  two 
supports  (little  horses);  it  is  then  scrubbed  carefully,  and  is 
washed  thoroughly  with  a  hose.  Pour  the  acid  into  the  water; 
it  is  dangerous  to  pour  water  into  the  acid. 

96.  Putting  On  and  Removing  Dandy  Rolls. — To  put  on  a 
dandy,  the  machine  tender  holds  it  vertical;  then,  with  the 
journal  in  one  hand,  he  makes  a  fulcrum  of  the  other  hand,  about 
2  feet  from  the  lower  end,  rests  his  elbow  on  the  shake  rail,  and 
gradually  lowers  the  upper  end.     His  back  tender  stands  on  the 


64 


PAPER-MAKING  MACHINES 


§6 


back  shake  rail,  catches  the  back  end,  and  fits  the  journal  to  its 
bearing.  The  machine  tender  gives  the  roll  a  slight  twirl  in  the 
direction  of  the  paper  travel  as  he  drops  the  roll  quickly  and  gently 
on  the  sheet;  this  can  be  done  without  breaking  the  sheet. 

To  remove  the  dand}^,  the  back  tender  and  the  machine  tender 
stand  as  before,  and  they  quickly  lift  the  roll  from  the  paper.  The 
back  tender  gives  his  end  a  quick  strong  lift,  but  not  too  strong, 
and  the  machine  tender  brings  the  roll  to  an  upright  position, 
where  he  can  balance  it;  he  generally  gets  a  good  wetting  from  the 
water  in  the  roll.  Wide  machines  have  a  plank  walk  across  the 
wire,  supported  from  the  frames,  so  the  roll  way  be  carried  off. 


COUCH  ROLLS 

97.  Purpose  of  Couch  Rolls. — The  function  of  the  couch  (pro- 
nounced cooch)  rolls  is  to  remove  water  from  the  formed  paper 
and  pack  the  fibers  firmly  together,  so  that  the  sheet  is  strong 
enough  to  pass  to  the  first  press.  The  top  couch  roll  is  couched 
toward  the  wet  end;  that  is,  it  is  not  directly  over  the  center  of 


1  fVidth  of  Machine 

10&' 

126" 

ISO" 

17S" 

200/' 

\  Diameter  of  Roll 

20" 

24" 

2e!' 

28" 

30" 

Fig.  42. 

the  lower  couch  roll,  see  Fig.  27,  but  bears  somewhat  on  the  wire, 
which  acts  as  a  couch.  This  arrangement  permits  water  to  be 
pressed  out,  and  it  causes  the  paper  to  be  gradually  squeezed 
between  the  wire  and  the  felt  jacket  on  the  upper  roll  before  being 
finally  squeezed  between  the  two  rolls.  The  couching  action 
guards  against  crushing  the  paper,  which  occurs  if  the  sheet  be 
too  full  of  water  when  entering  the  "nip"  between  the  two  rolls; 
and  the  water  has  a  better  chance  to  get  away  when  squeezed 
through  the  wire. 

98.  The  Lower  Couch  Roll. — A  section  through  a  lower  couch 
roll  is  shown  in  Fig.  42.     The  extension  A  provides  room  for  the 


§6  THE  MODERN  PAPER  MACHINE  65 

lifting  pipe  or  porter  bar,  Fig.  35,  to  fit  over;  C  is  the  journal,  and 
5  is  a  shell,  made  of  bronze,  gun  metal,  or  brass.  This  is  a  driving 
roll,  with  a  heavy  load  to  carry;  it  is  exposed  to  moisture,  and 
must  not  be  crowned.  A  comparison  of  Figs.  42  and  34  shows 
that  the  couch  roll  is  more  solidly  designed  than  the  breast  roll. 
As  is  the  case  with  the  breast  roll,  the  lower  couch  roll  is  not 
crowned  because  an  increase  in  the  diameter  at  the  middle  of  the 
roll  would  tend  to  stretch  the  wire  or  would,  in  any  case,  make  it 
travel  faster  at  the  center,  which  would  cause  strains  and  partially 
close  the  mesh.  In  most  cases,  the  lower  couch  roll  is  covered 
with  a  brass  or  gun-metal  shell. 

99.  Driving  the  Couch  Rolls. — The  lower  couch  roll  is  driven, 
and  it  pulls  the  wire  over  the  other  rolls  and  the  suction  boxes — a 
heav}'  load.  The  tendency  of  the  wire  to  slip  on  a  smooth  roll  is 
sometimes  counteracted  by  covering  the  roll  with  rubber.  A 
grooved  roll  is  sometimes  used  on  light  papers,  and  a  felt-jacket 
covered  roll  may  be  necessar}^  to  prevent  the  wire  from  marking  the 
paper,  the  weight  of  the  upper  roll  pinching  the  paper  against  the 
wire  and  the  lower  roll,  thus  impressing  the  mesh  of  the  wire  in 
the  soft  sheet. 

In  spite  of  all  attempts  to  devise  a  mechanical  drive — by 
means  of  a  slipping  belt,  etc. — the  upper  couch  roll  may  be  con- 
sidered as  driven  indirectly  from  the  lower  roll;  the  lower  roll 
drives  the  wire,  the  wire  carries  the  soft  sheet  of  paper,  and  the 
paper  really  drives  the  upper  couch  roll.  The  nature  of  this 
sheet  of  paper  demands  that  very  careful  attention  be  given  to 
the  condition  of  the  bearings,  to  lubrication,  and  to  the  setting 
of  the  upper  roll  with  reference  to  the  lower  roll,  both  as  regards 
their  position  and  the  prcssm-e  between  the  two  rolls. 

100.  Crushing — Cause  and  Remedy.— Adjustment  of  the 
pressure  between  the  couch  rolls  requires  consideration  of  the 
wetness  of  the  sheet,  to  prevent  crushing  of  the  sheet.  Crushing 
is  a  blotch\'  or  curdy  appearance  of  paper;  it  is  caused  by  a  too 
rapid  pressing  out  of  water,  which  pushes  the  fillers  into 
bunches. 

Crushing  is  common  with  heavy  papers,  the  fiber  of  which  may 
pile  up  before  the  roll,  hke  sand  in  front  of  a  small  wheel.  The 
remedy  is  to  increase  the  freeness  of  the  stock,  using  less  water 
(which  may,  however,  interfere  with  good  formation),  putting 
more  table  rolls  into  commission,  increasing  the  suction  on  the 


66 


PAPER-MAKING  MACHINES 


§6 


suction  boxes,  and  relieving  the  pressure  on  the  upper  couch  roll; 
it  may  also  be  overcome  by  using  a  suction  couch  roll. 

101.  Couch-Roll  Housings. — The  two  bearings  of  the  upper  roll 
are  carried  by  the  swinging  arms  of  couch  housings,  see  Fig.  43, 
which  shows  diagrammatically  two  typical  designs.  View  (a) 
shows  a  bevel  pinion  on  shaft  S,  which  is  actuated  by  a  hand 
wheel  (not  shown);  this  pinion  turns  the  larger  gear  A,  which 
acts  as  a  rotary  nut  and  pushes  or  pulls  on  the  screw  B,  thus 


Worm  and  Wheel  Bell  Crank  IToutlng 

Fig.  43. 

moving  the  coucher  arm  L  around  the  pivot  pin  P.  Eig.  43  ih) 
shows  a  worm  and  worm  wheel  instead  of  a  bevel  and  pinion. 
The  worm  W  is  actuated  by  a  hand  wheel  (not  shown) ;  it  turns 
the  wheel  G,  which  acts  in  the  same  manner  as  the  larger  bevel 
gear  A,  in  view  (a). 

The  design  shown  in  view  (a)  is  suited  to  fairly  narrow 
machines,  while  that  shown  in  view  (6)  is  for  wider-faced  and 
heavier  upper  couch  rolls  on  wider  machines,  the  worm-and- 
wheel  gearing  giving  a  larger  lifting  effect  than  the  bevel  gears. 
It  would  appear  to  be  well  worth  while  to  consider  the  use  of 
small  motors  for  furnishing  the  motive  power  to  lift  couch  rolls, 


§6 


THE  MODERN  PAPER  MACHINE 


07 


move  stretcher  rolls,  and  to  shift  belts  on  the  extremely  wide 
paper  machines  now  being  built. 

Referring  to  Fig.  43,  all  upper  arms  are  provided  with  weights 
and  levers,  attached  to  hook  H,  for  controlling  the  pressure 
between  the  rolls  across  the  machine.  As  will  be  explained 
later,  in  describing  the  press  part,  this  design  is  similar  in  all 
practical  details  to  that  used  for  any  press,  whether  for  a  couch 
roll  or  for  any  press  part  situated  farther  up  the  machine. 


Fig.  44. 

The  upper  couch  roll  is  covered  with  a  felt  jacket,  to  secure  a 
dry  sponge  effect  on  the  wet  paper;  it  is  a  descendant  of  the 
traveling  upper  felt  E,  Fig.  26.  Further  information  concerning 
the  use  of  the  couch  roll  and  the  jacket  will  be  found  in  Arts. 
117-122  and  141-146. 

102.  The  Guard  Board. — The  guard  board  is  so  placed  that  it 
squeezes  out  of  the  jacket  much  of  the  water  that  has  been 
absorbed  from  the  paper,  and  it  scrapes  off  lumps  of  pulp  that 
might  go  around  and  dent  the  wire.  With  the  water  is  a  certain 
amount  of  filler  and  fiber,  which  is  washed  out  at  the  ends  of  the 
roll  by  the  shower  pipe,  shown  on  the  press  side  of  the  guard  board 
in  Fig.  27,  and  at  F  in  Fig.  44.  The  guard  board  is  set  behind 
the  center  of  the  couch  roll;  this  makes  a  little  trough,  which  may 


68 


PAPER-MAKING  MACHINES 


§6 


§6  THE  MODERN  PAPER  MACHINE  69 

be  increased  by  a  small  roll  72  or  by  a  felt  wiper.     Pipe  F  and 
roll  R  may  be  supported  from  the  couch-roll  housing. 

The  guard  board  should  be  adjustable,  and  it  should  have  a 
flexible  edge  that  can  be  adjusted  to  give  a  uniform  pressure 
over  the  width  of  the  jacket.  Fig.  44  shows  a  typical  guard 
board.  A  plank  E  is  supported  by  cast-iron  brackets,  which  are 
bolted  to  the  top  of  the  bell-crank  arm  of  the  housing.  On  the 
front  of  this  plank,  the  light  guard-board  blade  D,  made  of 
maple,  is  held  in  place  by  a  series  of  spring  boxes  //;  through  these 
boxes,  double  thumb  sci'ews  pass,  wdiich  are  operated  from  above. 
If  a  part  of  the  jacket  is  running  wet,  a  turn  of  the  upper  thumb 
screw  B,  which  operates  on  one  of  the  springs,  gives  additional 
pressure  to  the  blade;  if  the  jacket  is  running  dry,  a  turn  of  the 
lower  thumb  screw  A  serves  in  like  manner  to  relieve  the  pressure 
of  the  blade.  Saw  cuts  in  the  upper  edge  of  the  blade  increase  its 
plial:)ility.  Since  the  guard  board  acts  like  a  brake,  a  gentler 
pressure  on  it  reduces  the  power  required  to  drive  the  Fourdrinier, 
and  it  lengthens  the  life  of  the  upper  couch-roll  jacket  and  of  the 
wire.  Perforating  the  shell  of  this  upper  couch  roll  facilitates 
removal  of  water  from  the  jacket. 


SUCTION  ROLLS 

103.  Suction  Couch  Roll. — Manj^  machines  are  equipped  with 
a  suction  couch  roll,  and  some  have  a  suction  press  roll  also;  the 
former  supplants  the  conventional  top  and  bottom  couch  rolls, 
and  the  latter  supplants  the  bottom  roll  of  a  pair  of  press  rolls. 
In  principle,  a  partial  vacuum  is  created  in  the  roll,  and  atmos- 
pheric pressure,  instead  of  roll  pressure,  packs  the  fibers  and 
squeezes  water  from  the  paper.  Many  advantages  are  claimed 
for  these  suction  rolls,  and  they  have  affected,  to  some  degree, 
the  design  of  the  newer  paper  machines. 

104.  Construction  and  Installation. — The  construction  of  the 
suction  couch  roll,  and  the  method  of  its  installation,  is  shown  in 
Fig.  45.  Here  (a)  is  a  longitudinal  section,  (6)  is  a  cross  section 
on  the  line  XX,  (c)  is  a  right  end-view,  and  id)  is  a  diagram 
showing  wire  and  felt.  A  perforated  bronze  shell  A  is  mounted 
in  substantial  bearings  B;  the  diameter  and  thickness  of  the 
shell  depend  on  the  width,  speed,  and  drag  of  the  wire,  and  the 
best  of  machine-shop  work  is  required.  The  shell  is  revolved 
at  the  speed  that  is  proper  to  drive  the  wire.     C  is  the  stationary 


70  PAPER-MAKING  MACHINES  |6 

suction  chamber;  it  is  connected  to  a  powerful  rotary  vacuum 
pump,  which  is  driven  from  a  constant-speed  Hne  shaft.  The 
pump  is  connected  at  V,  and  is  usually  located  in  the  basement. 
Contact  between  the  suction  chamber  and  the  inside  surface  of 
the  revolving  shell  is  made  with  special  packing,  which  is  held  in 
place  b}'  springs,  or  water,  or  compressed  air.  A  piston  arrange- 
ment D,  operated  by  shaft  and  handle  H,  is  provided  on  the  roll,  to 
adjust  the  length  of  the  suction  area  to  accommodate  any  width 
of  sheet  made  on  the  machine.  This  piston  fulfills  the  same 
purpose  as  the  pistons  1  in  Fig.  38.  The  chamber  C  need  not  be 
vertical,  it  may  be  swung  back  or  forward.  In  view  {d),  the 
small  roll  R  is  a,  light  aluminum  roll,  which  is  sometimes  used  to 
help  maintain  the  proper  draw  of  the  sheet  between  the  suction 
couch  roll  and  the  first  wet  felt. 

105.  Amount  of  Vacuum. — The  degree  of  vacuum  that  can  be 
maintained  in  the  suction  couch  roll  depends  largel}'^  upon  the 
weight  and  character  of  the  paper  made;  about  15  inches  of  mer- 
cury is  a  fair  average,  being  least  on  free  stock  and  on  thin  paper. 
The  shell  A  is  driven  by  gear  G  from  pinion  T,  shown  in  end 
view  (c).  It  is  to  be  noted  that  a  suction  couch  roll  requires 
more  power  for  its  operation  than  the  ordinary  pair  of  rolls. 
Since  the  shell  is  perforated,  the  ordinary  strength  formulas  do 
not  appl}^  when  designing  these  rolls. 

106.  Operation  of  Suction  Rolls. — In  order  to  understand  the 
operation  of  the  suction  rolls,  it  must  be  borne  in  mind  that  after 
the  web  of  paper  has  been  formed  on  the  Fourdrinier  wire,  the 
essential  remaining  problem,  insofar  as  the  paper  machine  itself 
is  concerned,  is  largely  one  of  removing  the  water  that  is  in  the 
sheet;  and  this  is  accomplished  by  the  suction  boxes,  the  pressure 
of  the  couch  and  press  rolls,  and  by  evaporation.  There  are 
different  ways  in  which  the  necessary  pressure  may  be  applied 
at  the  wet  end.  With  present-day,  relatively  high,  operating 
speeds,  the  water  must  be  eliminated  very  rapidl}-  from  the 
newly  formed  and  tender  sheet;  yet,  if  this  be  done  violently, 
the  finish  and  strength  of  the  paper  suffer,  to  say  nothing  of  the 
breaks  that  follow. 

107.  How  the  Pressure  Acts. — In  the  case  of  the  conventional 
couch  and  press  rolls,  most  of  the  pressure  is  exerted  on  the  line 
of  contact  of  the  top  and  bottom  rolls.     This  line  of  contact  is, 


§6  THE  MODERN  PAPER  MACHINE  71 

of  necessity,  very  narrow;  and  since  the  resulting  pressure  is 
tremendous,  per  unit  of  contact  area,  the  water  is  violently 
forced  from  the  web  of  paper  as  it  passes  between  the  rolls.  Some 
deranging  of  the  fibers,  or  a  partial  breaking  down  of  the  fibrous 
structure  that  has  been  so  carefully  built  up  in  the  forming  of  the 
sheet,  can  scarcely  be  avoided  with  such  pressing. 

With  suction  rolls,  line  pressure  is  replaced  by  atmospheric 
pressure,  which  is  both  constant  and  uniform,  and  is  applied  to 
a  controllable  unit  of  area  on  the  moist  paper.  Instead  of  a 
great  pressure  on  a  narrow  contact,  there  is,  with  the  suction  roll, 
a  lighter  and  milder  pressure,  which  is  distributed  over  a  greater 
area. 

108.  Manner  in  Which  Suction  Roll  Acts. — The  suction  couch 
roll  eliminates  entirely  the  necessity  of  the  old  top  couch  roll, 
with  its  felt  jacket  and  guard  board,  both  of  which  require 
considerable  attention,  and  which  are  responsible  directly  for 
many  of  the  troubles  of  the  machine  tender,  such  as  crushing, 
pitch  spots,  wire  marking,  pick-ups,  and  accidents  to  wires.  The 
avoidance  of  these  troubles  means  greater  production. 

The  suction-couch  roll  does  not  displace  the  regular  flat  suction 
boxes  on  the  wire;  but  the  suction  can  usually  be  kept  less,  thus 
putting  a  smaller  strain  on  the  wire  and  giving  it  a  longer  life. 
Damp  streaks  are  avoided,  since  the  atmospheric  pressure  is 
uniform;  the  wires  glide  easily  and  run  longer;  and  clearer  water- 
marks are  possible,  when  no  top-couch  roll  is  used. 

Suction  rolls  are  in  operation  in  machines  running  at  speeds 
up  to  and  above  1000  ft.  per  min.,  and  the  variation  in  the  weight 
of  papers  being  made  is  from  8  to  300  pounds. 

109.  Manner  in  Which  Paper  Should  Be  Taken  off  the  Wire.— 

When  starting  the  machine  and  taking  the  paper  off  the  wire, 
it  is  very  important  that  the  sheet  be  picked  off  the  wire  below 
the  suction  area.  The  paper  will  leave  the  wire  more  freely 
when  using  the  suction  couch  roll  than  with  the  old  couch  rolls, 
provided  it  be  taken  off  low  enough  to  avoid  the  effect  of  suction. 
The  wire  must  not  be  struck  hard  when  picking  up  the  ribbon 
(Art.  52).  In  several  cases,  wires  have  been  ruined  in  this  way, 
or  when  trying  to  pick  the  sheet  off  the  suction  area. 

On  light-weight  sheets  and  on  machines  operating  at  high 
speeds,  it  is  convenient  to  make  use  of  a  patented  compressed-air 
nozzle,  to  blow  the  ribbon  from  the  wire  onto  the  first  felt.     If 


72  PAPER-MAKING  MACHINES  §6 

unusual  difficulty  be  experienced  with  the  draw,  it  can  usually 
be  traced  to  the  felt  suction  box;  for  which  reason,  this  box  should 
be  equipped  with  a  vacuum  regulator  that  can  be  weighted  to 
change  the  degree  of  vacuum  carried.  As  the  vacuum  increases, 
the  paper  will  run  down  where  it  leaves  the  wire;  and  as  the 
vacuum  decreases,  the  draw  tightens;  because  the  felt  runs  slower 
or  faster,  respectively.  In  some  installations,  the  regulation  of 
the  felt  suction  box  is  so  close  that  the  additional  removal  of  an 
ordinary  f-inch  washer,  used  as  a  weight  on  the  vacuum  regulator 
valve,  will  change  the  draw  of  the  paper  perceptibly.  If  no 
draw  roll,  as  R  in  Fig.  45(d),  is  used,  and  the  sheet  is  drawn  too 
tight  between  the  wire  and  the  felt,  the  sheet  will  be  spotted; 
and  if  it  be  allowed  to  run  too  slow,  it  Avill  give  trouble  on 
the  felt. 

The  pistons  D,  Fig.  45,  should  be  carefully  adjusted  to  the 
width  of  the  wet  sheet.  If  the  pistons  are  not  out  far  enough, 
the  edges  of  the  sheet  will  run  wet,  and  the  sheet  is  apt  to  wrinkle 
on  the  felt.  Sometimes  the  edges  will  give  a  little  trouble,  if  the 
deckle  straps  are  worn  and  leakj^;  in  such  cases,  either  re-grind 
the  deckle  strap  or  make  use  of  a  squirt  on  either  side  of  the 
sheet,  to  cut  away  the  fringed  edges.  If  the  pistons  are  put  too 
far  out,  there  will,  of  course,  be  an  unnecessary  reduction  in  the 
vacuum,  because  of  the  extra  air  being  admitted. 

110.  Efifect  of,  and  Prevention  of,  Lumps. — When  the  suction 
couch  roll  is  used  without  a  suction  roll  on  the  first  press,  lumps 
(if  they  occur  on  the  sheet)  may  cause  a  breakdown  at  the  first 
press  roll.  The  proper  remedy  is  to  get  rid  of  the  lumps,  which 
are  usually  caused  by  dirty  screens  that  are  in  need  of  repair. 
If  the  cause  of  the  lumps  cannot  be  determined,  a  rubber  dandy 
roll  may  be  run  on  top  of  the  sheet,  over  the  suction  couch  roll. 
This  is  a  soft  rubber-covered  roll,  of  small  diameter,  and  only 
heavy  enough  to  squeeze  the  surplus  water  out  of  such  lumps;  it 
also  has  the  tendency  to  close  up  the  sheet  and  produce  a  higher 
vacuum.  Some  kinds  of  paper  will  not  stand  for  its  use,  however; 
and  it  is  not  recommended,  except  in  special  cases. 

If  the  machine  is  not  already  so  equipped,  the  addition  of  a 
flat  suction  box  on  the  first  felt  will  help  to  lay  the  paper  flat  on 
the  first  felt,  and  it  will  help  to  regulate  the  draw,  as  previously 
explained. 


§6  THE  MODERN  PAPER  MACHINE  73 

THE  STRETCH  ROLL 

111.  Varying  the  Tension  of  the  Wire.— Fig.  27  shows  a 
stretch  roll  12  on  the  inside  of  the  wire,  which  is  provided  with 
a  hand-operated  screw,  so  the  stretch  roll  can  be  moved  up  or 
down,  in  a  vertical  direction,  according  to  whether  the  wire 
tension  is  to  be  decreased  or  increased.  It  is  not  necessary  that 
a  Fourdrinier  wire  be  very  tight ;  the  pull  of  the  couch  roll  on  the 
wire,  which  drives  all  the  table  rolls  and  the  breast  roll,  will 
keep  the  forming-table  part  of  the  wire  tight,  even  if  the  return 
of  the  wire  be  loose.  When  using  the  stretch  roll,  the  machine 
tender  can  actually  pull  a  wire  apart,  if  he  is  not  careful,  and 
he  may  easilj'  put  an  undue  strain  on  it.  It  is  best  to  order  the 
wire  long  enough  to  permit  the  stretch  roll  to  rest  in  a  loop. 

112.  Stretching  of  the  Wire.^ — If  the  wire  runs  nearly  straight 
across  the  stretch  roll  from  the  neighboring  rolls,  it  is  much  more 
likely  to  be  overstretched,  without  realizing  it,  than  when  the 
stretch  roll  hes  in  more  of  a  loop.  The  tension  of  the  wire  due 
to  the  stretch  roll  only  should  not  exceed  3  pounds  per  inch  of 
face  of  the  wire,  and  this  tension  should  not  be  increased  or 
decreased  as  the  wire  grows  older.  If,  because  of  wear  and  tear 
due  to  being  in  service,  the  tension  of  a  wire  be  altered,  the  joints 
of  the  mesh  will  loosen  and  begin  to  work ;  and  the  wire  will  then 
shear  itself  into  cracks  much  more  quickly  than  if  the  original 
tension  had  been  maintained.  The  wire  of  the  Fourdrinier 
will  naturally  get  a  little  longer  as  it  gets  older,  largely  because 
of  the  pull  and  the  friction  of  the  suction  boxes.  The  increase 
in  length  of  a  wire  may  be  taken  care  of  by  a  proper  use  of  the 
stretch  roll,  without  increasing  the  tension  of  the  wire.  The 
stretch  roll  should  be  used  very  carefully,  in  order  not  to  put 
excessive  tension  on  the  wire. 


ELEVATING  THE  FOURDRINIER  WIRE 

113.  Elevating  Device. — Fig.  27  shows  an  elevating  device 
that  is  often  used  on  high-speed  news  machines;  different  makers 
use  different  devices.  The  object  sought  is  to  give  the  wire  such 
a  pitch  that  the  stock  emerging  from  the  slice  or  flow  box  will 
travel  down  grade,  and  at  about  the  same  speed  as  the  wire  is 
traveling;  this  results  in  far  better  formation  and  more  uniform 
quality.     It  will  be  seen  that  the  beams  K,  hung  on  either  side 


74  PAPER-MAKING  MACHINES  §6 

of  the  machine,  carry  the  table  bars  13,  table  rolls  5,  and  breast 
roll  4,  and  also  the  deckle  parts.  The  save-all  boxes  are  also 
supported  on  the  beams  K.  The  hand  wheel  W  shown  at  the 
flow  box  is  on  a  shaft  that  carries  two  worms,  which  actuate  a 
big  worm  wheel  on  either  side  of  the  machine.  These  worm 
wheels  are  keyed  to  vertical  shafts,  which  have  screws  cut  on  the 
bottom  ends,  the  screw  threads  being  above  the  end  bearings  in 
which  these  vertical  shafts  turn.  These  screws  turn  in  nuts, 
which  are  a  part  of  the  flow-box  ends  of  the  supporting  beams  K. 
As  the  vertical  shafts  are  turned  bj'  the  operator  at  the  hand 
wheel,  the  nuts  on  the  ends  of  the  beams  K  travel  up  or  down, 
lifting  or  lowering  the  flow  box,  the  breast  roll,  and  the  wet  end 
of  the  Fourdrinier. 

In  wide  machines,  the  elevating  devices,  which  are  similar  to 
that  just  described,  are  operated  by  a  small  motor  instead  of  by 
a  hand  wheel.  The  majority  of  paper  machines  are  so  designed 
that  the  breast  roll  can  be  raised  or  lowered  2  or  3  inches  above 
or  below  the  level  of  the  couch  roll.  High-speed  news  machines 
are  now  often  built  with  a  permanent  pitch  of  18  inches  or  more 
to  the  wire. 

MANAGEMENT  OF  THE  FOURDRINIER  PART 


HOW  TO  PUT  ON  A  NEW  WIRE 

114.  Removing  the  Old  Wire. — One  of  the  most  important 
tasks  of  the  machine  crew  is  that  of  putting  on  a  new  wire. 
When  changing  wires,  first  see  that  there  is  no  danger  of  any  roll 
falling  out  of  its  bearings;  then  make  two  short  cuts  in  the  old 
wire,  about  an  inch  apart  and  close  to  the  couch  roll;  put  in  the 
clutch,  and  run  the  cut  part  onto  the  lower  couch  roll,  past  the 
nip;  after  which,  stop  the  wire.  Take  the  inch-wide  strip  that 
has  been  started  by  the  two  cuts,  and  tear  it  off  right  across 
the  machine;  put  in  the  clutch,  and  roll  the  wire  onto  a  wood 
core  until  the  roll  is  large  enough  to  lie  between  the  lower  couch 
roll  and  the  first  press-felt  roll;  then  start  up  the  wet  felt,  and 
roll  the  old  wire  up  between  the  first  press-felt  roll  and  the 
coucher  (couch  roll).  The  roll  is  started  with  the  core  lying  on  the 
top  of  the  wire.     The  old  wire  should  be  preserved ;  it  is  valuable. 

The  machine  tender  then  takes  off  the  slices  and  folds  back 
the  apron;  when  possible,  lift  the  deckle  frames  and  sHces  com- 


§6 


THE  MODERN  PAPER  MACHINE 


75 


pletely  off  the  machine.  The  crew  should  now  take  out  the 
suction  boxes  and  table  rolls,  laying  them  on  the  tending  floor, 
in  such  order,  that  each  part  will  be  returned  to  the  same  place 
or  to  its  own  bearings,  when  the  new  wire  is  put  in.  All  these 
parts  should  be  well  cleaned  and  scrubbed,  to  remove  any  clay  or 
pulp. 

Next  remove  the  save-all  boxes  and  the  wire-carrying  rolls; 
the  latter  are  usually  lifted  out,  they  may  be  slid  out  on  planks, 
in  the  case  of  wide  machines  and  heavy  rolls.     Lastly,  remove  the 


Fig.  46. 


breast  roll,  by  means  of  the  rails  and  light  trucks,  upon  which  the 
roll  is  lifted  with  the  chain  hoist.  Now  send  for  the  new  wire,  and 
have  the  millwright  plane  the  suction-box  covers.  The  upper 
couch  roll  is  lifted  by  means  of  the  bell  cranks  and  gear,  and  the 
cap  of  the  lower  roll  bearing  is  removed. 

The  porter  bar  is  placed  in  the  wire  by  putting  it  on  the  end  of 
the  wood  spar  A,  Fig.  46(a),  which  is  in  the  wire  when  purchased 
and  received.  As  this  spar  is  pushed  out,  carefully  follow  it 
with  the  porter  bar.  When  the  spar  has  thus  been  replaced  with 
the  porter  bar,  one  end  of  the  bar,  Fig.  35,  is  placed  securely  over 
the  extension  of  the  lower  couch  journal,  and  the  other  end  is 
lifted  by  a  chain  fall  (block  and  tackle)  and  held  in  position,  so 
that  the  end  of  the  couch  roll  is  carried  at  the  right  height  to  allow 


76  PAPER-MAKING  MACHINES  §6 

the  new  wire  to  be  slipped  over  it.  The  lower  bearing  is  removed, 
and  all  parts  that  might  touch  the  wire  are  wiped  clean.  The 
new  wire  is  then  carefully  slid  over  the  lower  couch  roll,  great 
care  being  taken  not  to  kink  it.  Kinks  form  very  quickly  and 
easily,  and  they  practically  ruin  a  wire. 

115.  Putting  on  the  New  Wire. — The  roll  of  new  wire  is  now 
placed  on  top  of  the  lower  couch  roll,  Fig.  46(6),  spar  A  is 
replaced  in  the  wire  roll,  and  the  wire  is  unrolled,  as  indicated 
by  the  arrows;  the  wire  is,  of  course,  far  longer  than  is  indicated  in 
the  figure.  Spar  A ,  together  with  the  wire  on  it,  is  carried  toward 
the  flow  box  sufficiently  far  to  permit  the  breast  roll  to  be  placed 
inside  of  the  wire,  a  few  table  rolls  being  replaced  to  prevent  much 
sagging;  the  breast  roll  is  slid  on  a  plank  (or  rails),  laid  inside  the 
wire,  until  it  can  be  placed  in  its  bearings,  after  which,  the  plank 
is  removed,  care  being  taken  not  to  injure  the  wire.  Only  the 
rolls  under  the  wire  (except  the  upper  couch  roll)  may  be  left  in 
the  machine.  The  new  wire  should  be  carefully  examined  for 
defects;  if  any  are  found,  roll  up  the  wire  carefully  and  put  it 
back  in  its  box  for  return  to  the  manufacturers;  but  don't 
blame  the  wire  man  for  the  result  of  carelessness  in  the  mill. 

Next  put  the  supports  and  save-alls  in  their  proper  places,  and 
then  the  table  rolls,  one  by  one;  the  suction  boxes  follow,  then  the 
carrying  rolls,  the  guide  roll,  and,  lastly,  the  stretcher  roll.  The 
greatest  of  care  should  be  taken  to  see  that  there  are  no  loose  parts 
or  rolls  that  can  possibly  fall  on  the  new  wire;  that  top  brasses, 
pins,  screws,  bolts,  etc.  are  all  in  place;  that  the  shower  pipes  are 
up,  the  doctors  replaced,  and  that  the  guide  mechanism  is  in 
place.  The  palm  or  palms  on  the  guide  bar  must  clear  the  edge 
of  the  wire  by  about  /g  inch.  See  that  all  pipe  connections  are 
tight. 

The  end  of  the  save-alls  should  not  be  close  enough  to  the 
breast  roll  to  allow  any  stock  to  become  lodged  between  them. 
Since  the  back  of  the  breast  roll  passes  down  from  the  save-alls 
to  the  breast-roll  doctor,  it  retains  stock;  therefore,  a  strong  shower 
pipe  should  play  on  it  just  above  the  doctor,  to  wash  accumula- 
tions off  this  doctor  and  through  the  wire  or  to  one  side,  by  a 
trough.  The  doctor  should  have  a  felt  or  a  rubber  edge,  to  keep 
the  breast-roll  surface  clean  and  to  keep  any  stock  from  travehng 
up  between  the  wire  and  the  breast  roll,  which  would  cause  ridges 
in  the  wire.  The  pressure  of  the  doctor  against  the  breast  roll 
should  be  as  light  as  possible  and  still  permit  it  to  clean  the  roll. 


§6  THE  MODERN  PAPER  MACHINE  77 

Any  extra  pressure  will  act  like  a  brake,  which  will  increase  the 
work  that  the  wire  must  do  in  turning  the  roll.  The  pulp  thus 
scraped  off  by  the  doctor  may  be  made  to  fall  into  the  save-all 
box. 

116.  Care  of  the  Wire. — Proper  care  of  the  Fourdrinier  part  of 
the  machine,  either  when  idle  or  when  being  prepared  for  service, 
is  extremely  important;  both  for  the  sake  of  the  machine  itself 
and  for  the  resulting  saving  in  the  expensive  wire.  Under  care- 
less management,  the  wire  may  last  only  a  few  days,  when  several 
weeks  of  service  may  be  obtained  from  it,  if  properly  attended  to. 
Generally  speaking,  the  life  of  the  wire  largely  depends  on  the 
machine  tender. 

When  putting  on  a  wire,  the  little  patches  of  hard  pulp  that 
stick  to  the  rolls  are  sure  to  cause  trouble,  unless  they  are 
thoroughly  removed.  Again,  when  putting  the  wire  on,  kinks 
are  very  liable  to  be  forced  in  it,  and  the  bends  so  produced 
always  develop  into  cracks.  It  is  necessary  that  the  seam  on  the 
wire  be  kept  straight,  and  this  cannot  be  effected  unless  the 
guide  roll  and  stretch  roll  are  square  with  the  machine,  and  both 
are  level. 

117.  Testing  Squareness  of  Table  Rolls. — The  proper  way  to 
test  the  squareness  of  the  table  rolls  across  the  machine  is  to 
measure  with  a  tape  line  or  a  pair  of  trams  (two  sharp  pointers, 
at  right  angles  to  and  adjustable  along,  a  long  stick  or  bar),  to 
ascertain  whether  the  distance  between  the  ends  of  the  several 
rolls  is  the  same  on  either  side  of  the  machine.  Care  should  be 
taken  to  select  the  points  at  easy  places  where  the  measurement 
begins,  and  center-punch  marks  should  be  made  to  locate  these 
measuring  points.  The  punch  marks  should  be  made  directly 
over  the  center  of  the  journals  of,  say,  the  first  press  roll  or  the 
couch  roll. 

When  satisfied  that  the  measurements  are  the  same  on  both 
sides  of  the  machine,  measure  diagonally  to  see  if  the  rolls  are 
square  with  the  machine;  for  instance,  see  if  the  measurements 
between  the  centers  of  the  journals  of  the  couch  rolls  and  the 
breast  roll  are  equal  on  either  side.  It  is  also  quite  as  important 
to  see  that  the  measurement  from  the  center  of  the  front  journal 
of  the  couch  roll  to  the  center  of  the  back  journal  of  the  breast 
roll  is  the  same  as  from  the  center  of  the  back  journal  of  couch  roll 
to  the  center  of  the  front  journal  of  the  breast  roll. 


78  PAPER-MAKING  MACHINES  §G 

These  distances  may  be  too  great  to  be  measured  easily;  but 
they  can  be  checked  by  measuring  diagonally  from  the  couch-roll 
journals  to  the  first  table-roll  journals,  or  to  the  suction  boxes, 
making  continual  diagonal  measurements  until  the  breast  roll 
is  reached.     The  measuring  should  be  done  with  a  steel  tape. 

118.  Leveling  and  Lining-Up  the  Table  Rolls. — When  the  rolls 
have  been  squared,  carefully  level  them  across  the  machine. 
Line  up  the  rolls  by  placing  a  tight  wire  from  the  top  of  the  breast 
roll,  and  see  that  light  just  shows  between  the  wire  and  the  top  of 
each  roll;  this  wire  should  be  drawn  tight,  from  the  top  of  the 
l)reast  roll  to  the  top  of  the  guide  roll.  If  the  breast  roll  has  been 
raised  or  lowered,  the  wire  should  be  straight  from  the  top  of  the 
breast  roll  to  the  top  of  the  last  table  roll  next  the  hinge  or  break 
in  the  table  bars;  see  Fig.  27.  If  adjustments  are  required,  they 
should  be  made  by  the  millwright  or  master  mechanic. 

119.  Squaring  the  Other  Rolls. — The  couch  roll  and  all  other 
rolls  must  be  kept  square  with  the  machine;  periodical  checking 
of  the  squareness  of  the  rolls  will  often  prevent  undue  strains  on 
the  wire.  The  upper  couch  roll  should  be  so  placed  that  a  plumb 
line  dropped  through  the  center  of  the  journal  will  be  nearer  to  the 
wet  end  of  the  machine  than  a  line  similarly  dropped  through  the 
center  of  the  lower  couch  roll.  Great  care  must  be  taken  in 
couching  (off-setting)  the  top  roll.  First  see  that  the  distance 
between  these  plumb  lines  is  the  same  at  the  front,  or  tending, 
side  of  the  machine  as  at  the  back,  or  driving,  side  of  the  machine; 
second,  that  the  amount  of  couch  is  as  much  as  possible,  without 
taking  the  weight  of  the  upper  couch  roll  off  the  lower  couch  roll 
and  placing  it  on  the  wire.  An  average  amount  for  the  couch  is 
about  4  inches,  but  will  vary  with  the  size  of  the  rolls.  Sighting 
over  two  straight  edges  placed  on  the  faces  of  both  rolls  front  and 
back  is  a  good  method  of  checking  your  work. 

120.  Amount  of  Stretch  in  the  Wire. — The  amount  of  stretch 
of  the  wire  should  not  be  tested  by  hand ;  it  is  much  better  to  use  a 
mechanical  tension  indicator  at  the  stretch  roll,  and  an  ordinary 
spring  balance  may  be  used  for  this  purpose.  Records  of  wire 
tensions  so  obtained  and  recorded  will  give  valuable  information 
as  to  the  effect  of  various  tensions  on  the  duration  of  a  wire. 
Take  care  not  to  stretch  the  wire  too  much. 

121.  Starting  a  New  Wire. — When  starting  a  new  wire,  start 
slowly,  have  all  the  shower  pijpes  working  and  the  hose  going,  so 


§0  THE  MODERN  PAPER  MACHINE  79 

no  stock  can  get  between  the  rolls  and  the  wire.  Note  whether 
the  wire  seam  is  raised  up ;  if  so,  pass  it  over  the  lower  couch  roll 
and  flatten  it  lightly  with  a  wooden  mallet.  If  the  seam  is  raised 
up,  it  will  cause  bubbles  aci'oss  the  sheet,  because  of  the  air  it 
traps  as  the  raised  part  passes  over  the  breast  roll.  This  trapped 
air  is  forced  through,  and  it  makes  its  escape  under  the  apron, 
carrying  with  it  the  frothy  sizing  compounds  left  by  the  waste 
water  in  the  meshes  of  the  wire. 

122.  Lubrication. — Lubricant  of  a  good  grade,  preferabl}'  a 
clean  mineral  grease,  should  be  used  on  the  table  journal  bearings, 
and  a  mineral  oil  of  approved  brand,  about  28°  Be.,  on  the  other 
roll  bearings.  The  wire,  which  acts  as  a  continuous  driving  belt 
with  the  lower  couch  roll  as  the  driving  pulley,  has  a  great  load 
to  carry,  and  this  can  be  largely  decreased  by  proper  attention  to 
the  lubrication  of  the  bearings. 


CLEANING  THE  WIRE 

123.  Souring  the  Wire. — If  it  can  be  avoided,  do  not  clean  the 
wire  with  acid;  but  if  this  appears  to  be  the  onh-  effective  method, 
dilute  the  acid  with  water — 5  parts  of  water  to  1  part  of  sulphuiic 
acid.  The  solution  can  be  apphed  to  the  wire  through  the 
shower  pipes  on  the  inside  of  the  wire.  This  process  is  called 
souring  the  wire.  The  weak  acid  solution  may  be  applied  on  the 
wire  as  it  comes  over  first  wire  roll.  Alwaj's  pour  the  acid 
into  the  water. 

A  good  way  to  clean  a  wire  with  an  acid  solution  (sometimes  a 
caustic  solution  is  used  for  this  purpose)  is  to  make  a  water-tight 
box,  in  which  the  lowest  outside  wire  roll  can  run.  The  roll, 
turning  in  the  solution,  will  then  sour  the  wire  evenly  all  over, 
and  the  wire  will,  in  its  turn,  carry  around  enough  solution  to 
sour  and  clean  the  whole  wire.  Be  sure  not  to  have  the  suction 
boxes  in  action  while  the  cleaning  process  is  going  on;  otherwise, 
the  acid  (or  caustic)  will  then  be  lost  before  it  reaches  the  dandy 
roll.  When  the  wire  and  dandy  stop  frothing  freely  from  the  acid 
bath,  they  are  practically  clean;  then  wash  off  all  the  acid  with 
a  hose,  and  clean  out  the  water-tight  box.  Keep  this  box  clean 
or  remove  it.  Remember  that  acid  acts  chemically  on  the  wire, 
and  that  it  must  therefore  be  well  diluted  and  afterwards 
thoroughly  washed  off. 


80  PAPER-MAKING  MACHINES  §6 

124.  Pitch  Troubles. — Pitch  or  grease  spots  in  the  wire  may 
be  removed  by  putting  a  strip  of  felt,  about  36  inches  wide, 
extending  across  the  machine,  on  the  inside  of  the  wire;  by 
means  of  a  small  jet  or  steam  hose,  about  j  inch  in  diameter,  the 
pitch  can  then  be  blown  from  the  wire  into  this  felt.  This 
arrangement  gives  a  sharp,  direct  blow  of  hot  steam  at  the 
pitch  spots  on  the  wire,  which  removes  them  so  quickly  that  it 
does  not  heat  the  wire.  Care  should  be  taken  not  to  hold  the 
steam  jet  too  long  in  one  place,  since  this  would  weaken  the 
weave  on  account  of  the  resulting  unequal  expansion  of  the  wire. 
It  may  be  mentioned  that  alcohol  and  ether  are  solvents  for 
pitch. 

While  the  stock  is  on  the  machine,  pitch  will  sometimes  accumu- 
late in  the  meshes  of  the  wire  or  on  the  suction  boxes.  If  on 
the  suction  boxes,  the  boxes  may  be  removed  while  the  wire  is 
running;  then  remove  the  pitch  and  replace  the  boxes. 

125.  Washing  the  Wire. — Wash  the  wire  plentifully  with  a 
hose  whenever  a  chance  is  offered;  this  keeps  the  meshes  open, 
washes  off  the  acid,  prolongs  the  life  of  the  wire,  improves  the 
appearance  of  the  paper,  and  reduces  the  work  on  the  suction 
boxes.  Be  careful,  also,  to  play  the  hose  well  and  carefully  on 
the  back  side  of  the  machine.  Sometimes  the  dirt  gets  washed 
only  from  the  front  to  the  back  side.  Many  of  the  troubles  on 
paper  machines  are  caused  by  the  fact  that  the  back  side  of 
the  machine  is  not  as  easily  taken  care  of  as  the  front  side; 
the  machine  tender  should  remember  this  when  working  on  his 
machine,  and  should  give  special  attention  to  the  back  side. 
The  front  side  is  not  so  liable  to  be  neglected.  When  washing 
down  with  a  hose,  lift  the  dandy  roll  off  the  wire,  so  as  to  keep  old 
froth  spots  from  getting  washed  onto  the  dandy.  Keep  water 
off  belts  and  motors,  and  remember  that  it  costs  money  to  pump 
water;  don't  waste  it. 

OPERATING  DETAILS  AND  TROUBLES 


WIRE,  APRON  CLOTH,  AND  SLICES 

126.  Action  of  the  Wire  Guide. — ^The  wire  guide  can  prolong  the 
life  of  a  wire  or  it  may  shorten  its  life,  according  to  its  mechanical 
condition.     If  the  guide  mechanism  is  kept  in  good,  sensitive 


§6  THE  MODERN  PAPER  MACHINE  81 

working  order,  it  will  guide  the  wire  without  undue  wear;  but 
if  it  works  stiffly,  it  ceases  to  be  a  protection  and  becomes  a 
source  of  injury,  by  creasing  and  cracking  the  edges. 

127.  Kinks  in  the  Wire. — A  kink  in  the  wire,  caused  by 
dropping  a  wire  brush  or  by  any  other  means,  can  be  removed  as 
follows:  First  grease  the  kink,  or  buckle,  bring  the  part  of  the 
wire  where  the  buckle  appears  over  the  stretch  roll,  then  sour  or 
wash  the  wire  with  acid  (a  4  to  1  solution  of  sulphuric  acid)  right 
across  the  portion  of  the  wire  where  the  buckle  appears.  The 
stretch  roll  can  then  be  set  up  until  the  buckle,  or  kink,  disappears; 
then  wash  off  the  acid  solution  with  a  hose.  A  kink  can  also  be 
removed  by  the  stretch  roll,  in  a  similar  manner,  b}^  heating  the 
buckle  or  kink  red  hot,  using  a  torch  made  of  a  handful  of  waste 
that  has  been  dipped  in  kerosene  and  attached  to  a  broomstick. 
The  result  of  this  is  that  the  wire  is  softened  and  the  kink  is 
removed,  instead  of  the  wire  being  weakened  by  acid;  and  the 
strength  of  the  wire  is  not  impaired. 

128.  Care  of  Apron. — If  the  apron  cloth,  frequently  called 
the  apron,  will  not  lie  flat,  but  tends  to  buckle  or  roll  up  on  the 
edge,  drench  it  with  hot  water  until  it  lies  flat  on  the  wire.  If 
the  machine  is  idle  for  a  long  time,  put  a  strip  of  wet  felt  on  the 
edge  of  the  apron;  then  fasten  the  brass  or  metal  angles  or  side 
pieces  to  the  apron,  as  far  under  the  deckle  pulley  as  is  possible 
without  touching  the  strap.     See  Art.  57. 

129.  Necessity  for  Uniform  Flow  of  Stock. — When  starting 
the  stock  onto  the  machine,  the  slices  should  be  so  adjusted  as  to 
keep  the  level  of  the  stock  higher  on  the  side  next  the  apron 
than  on  the  machine  side;  in  this  way,  the  speed  of  the  stock  is 
kept  approximately  as  high  as  the  speed  of  the  wire  for  high- 
grade  paper.  If  the  stock  is  flowing  onto  the  wire  at  a  slower 
speed  than  the  wire  is  moving,  ripples  and  waves,  the  so-called 
fish  tails,  will  appear  on  the  stream  of  stock  up  to  the  point 
where  the  speeds  are  equal.  If  equality  of  speed  be  not  attained 
before  the  paper  is  nearly  formed,  the  increasing  viscosity  of  the 
stock,  as  it  gets  drier,  prevents  the  smoothing  out  of  the  surface, 
and  these  ripples  or  waves  become  permanent;  the  paper  then 
lacks  uniformity  of  strength,  finish,  and  thickness,  and  it  will,  in 
such  case,  often  break  before  it  reaches  the  calenders. 

130.  Regulating  the  Slices.— The  sHces  are  regulated  to  suit 
the  kind  of  stock  and  the  speed  of  the  wire.     When  the  stock  is 


82  PAPER-MAKING  MACHINES  §6 

fijie  (or  slow)  and  carries  water  well,  the  slices  should  be  kept 
down,  especially  when  making  wove  papery  no  more  water  should 
be  used  than  is  necessary  to  close  the  sheet,  and  as  little  shake  as 
possible  should  be  allowed.  The  suction  box,  or  boxes,  before 
the  dandy  roll  should  not  draw  too  hard. 

When  making  laid  paper,  the  slices  are  raised  a  little  higher 
above  the  wire  than  when  making  wove  paper;  more  water  is 
required,  more  suction  is  necessary  on  the  first  boxes,  and  the 
stock  is  generally  more  free.  The  stock  being  more  dilute,  the 
head  back  of  the  slice  (if  the  slice  be  not  raised  enough)  will  force 
the  stock  to  move  more  quickly  than  the  wire,  and  some  of  the 
effects  of  the  shake  will  then  be  lost. 

When  making  light-weight  papers,  the  tendency  is  to  let  the 
stock  flow  more  slowly  than  the  wire  is  moving.  When  this 
occurs,  keep  the  stock  back  of  the  slices  at  a  higher  level,  so  as  to 
create  more  head  and  get  the  necessary  volume  of  stock  for  the 
same  slice  opening. 

When  the  stock  is  flowing  too  quickly  under  the  slices,  which 
is  often  the  case  when  making  the  heavier  papers,  reduce  the 
head  back  of  the  slices  until  the  speed  of  flow  is  the  same  as  the 
speed  of  the  wire,  by  increasing  the  slice  opening  or  by  shutting 
off  some  white  water.  If  the  dandy  roll  tends  to  rise,  there  is 
too  much  water  in  the  sheet;  when  this  happens,  increase  the 
suction  on  the  first  boxes  and  give  more  shake.  The  thicker  the 
sheet  the  more  shake  that  is  required. 


STOCK  TROUBLES 

131.  Manner  of  Running  Stock. — When  making  envelope, 
cartridge,  or  any  paper  for  which  stock  may  have  been  kept  too 
long,  and  is  therefore  soft,  it  is  necessary  to  use  plenty  of  water, 
raise  the  slices,  and  give  a  vigorous  shake.  Be  careful  not  to 
give  too  much  shake,  or  the  edges  of  the  paper  will  be  thin,  on 
account  of  the  back  washing  from  the  deckle  straps. 

It  is  sometimes  necessary,  due  to  the  poor  design  of  the  flow 
box  and  apron  board,  to  check  the  flow  of  stock  at  certain  points 
across  the  slices,  with  pieces  of  paper,  etc.,  so  as  to  get  an  even 
stream  across  the  machine.  Weights  are  often  placed  on  the 
apron,  in  the  stream  of  stock,  to  correct  such  uneveness  of  flow. 
At  the  places  where  these  obstacles  occur,  trouble  may  be  expected 
at  the  dandy.     It  is  better  to  correct  for  these  faults  by  raising 


§6  THE  MODERN  PAPER  MACHINE  83 

the  slices  a  little,  using  more  water,  and  increasing  the  flow  from 
the  box, 

132.  If  the  stock  is  long,  and  is  also  soft  from  long  storage, 
run  slowly;  but,  even  then,  do  not  expect  a  good  sheet  of  paper. 
When  the  stock  is  soft  and  fine,  it  will  look  crushed,  and  it  will 
stick  to  the  first  press  roll;  use  as  little  shake  as  possible  and  as 
much  suction  as  possible. 

With  soft,  fine  stock,  weight  the  couchers  well,  and  set  the 
guard  board  close  to  the  jacket,  but  keep  the  jacket  wet  enough 
to  prevent  rubbing  off  dust  from  jacket  or  board.  Then  use 
but  little  weight  on  the  first  press,  and  keep  the  wet  felt  fairly 
tight.  If  sticking  still  continues,  use  turpentine  on  the  press  roll, 
after  the  paper  is  down  on  the  felt,  and  keep  turpentine  on  the 
press  roll  until  the  tendency  to  stick  and  climb  up  the  roll  is 
sufficiently  reduced, 

133.  To  Keep  Water  in  the  Stock. — In  making  a  high  grade  of 
paper  on  a  long  wire,  the  paper  may  have  a  dull,  crushed  look, 
more  especially  if  it  be  a  wove  paper,  on  account  of  too  much 
water  leaving  the  stock  at  the  table  rolls  before  proper  formation 
is  accomplished.  To  remedy  this,  prepare  the  stock  fine,  allow 
the  water  to  stay  in  the  sheet,  and  allow  the  shake  to  get  in  its 
work,  by  lowering  a  sufficient  number  of  table  rolls  to  keep  them 
from  touching  the  wire.  It  may  here  be  remarked  that  some 
paper  makers  do  not  believe  in  the  possibilities  of  judiciously 
varying  the  number  of  table  rolls  in  action. 

It  is  to  be  noted  that  if  the  number  of  table  rolls  are  reduced 
to  the  right  number  and  the  quantity  of  water  is  reduced  to  the 
right  quantity,  then  the  paper  will  reach  the  couch  roll  with  a 
larger  proportion  of  the  sizing  and  loading  originally  placed  in  the 
beater  than  when  more  water  is  used  and  more  table  rolls  are  in 
action.  It  is  common  practice  on  high-speed  news  machines 
to  remove  several  table  rolls  in  the  summer  time,  when  the  stock 
is  freer,  so  as  to  prevent  too  much  damage  at  the  forming  table. 

By  raising  the  breast  roll,  saj^  18  inches  higher  than  the  couch 
roll,  a  long  wire  can  be  used;  this  will  carry  the  water  well  down 
to  the  suction  boxes,  and  the  machine  can  run  at  a  speed  of  over 
800  ft.  per  min.  on  such  papers  as  news.  An  even  greater  incli- 
nation of  the  wire  is  used  at  high  speeds,  up  to  1200  ft,  per  min. 
If  it  be  desired  to  use  plenty  of  water  to  carry  the  stock  well 
down  the  wire,  and  it  is  desired  to  close  the  paper  well  by  using 


84  PAPER-MAKING  MACHINES  §6 

plenty  of  shake,  the  breast  roll  may  be  lowered,  say  2  or  3  inches 
below  the  couch,  and  the  amount  of  water  may  be  used  that  is 
necessary  when  using  a  short  wire ;  fine  papers  can  then  be  made 
at  100  to  300  ft.  per  min. 

134.  Increasing  Capacity  of  Machine. — By  clear  thinking 
and  reasoning  from  the  observed  results  of  certain  manipulations, 
the  paper  maker  can  largely  increase  the  capacity  of  his  machine, 
not  only  with  respect  to  output  and  speed  but  also  with  respect 
to  quality  of  finish  and  formation.  He  has  control  of  the  quan- 
tity of  water  and  the  amount  of  shake;  he  can,  on  the  same 
machine,  control  the  finish  and  felting  by  getting  exactly  the 
right  amount  of  water  out  of  the  stock  at  the  dandy  roll;  at  the 
same  time,  he  can  have  plenty  of  water  in  the  stock  at  the  slices, 
to  allow  the  shake  to  get  high  speed  and  good  felting.  He  can 
raise  the  breast  roll  and  then  correct  the  poor  felting  that  may 
result  therefrom,  bj^  removing  some  table  rolls;  he  can  again  get 
good  felting  by  lowering  the  breast  roll,  and  may  still  maintain 
his  speed  by  increasing  the  head  back  of  the  slice  and  also  increas- 
ing the  number  of  table  rolls.  The  amount  of  the  suction  on  the 
first  boxes  gives  him  another  instrument  for  increasing  the 
efficiency  of  operation,  and  this  is  also  under  his  control.  How- 
ever, it  is  not  practical  or  sensible  to  make  experiments  that 
would  cut  down  production;  unless  the  paper  maker  can  estimate 
quite  accurately  what  the  result  will  be,  it  would  be  foolish  to 
experiment. 

135.  When  starting  the  paper  machine  on  a  new  order,  examine 
the  stock;  if  it  is  free,  increase  the  water  supply.  If  this  be 
not  done,  the  screens  will  fill  up  and  the  wire  will  be  flooded  with 
excess  stock.  On  news,  kraft,  wrapping,  and  cheap  book,  start 
with  plenty  of  water,  say  300  parts  of  water  to  1  of  stock,  and  let 
the  excess  return  to  the  regulating  box,  through  the  save-alls 
and  white-water  pump. 

On  slow  stock, — rag  paper,  fine  writings,  ledgers,  bonds,  etc., — 
it  is  best  to  start  with  about  50  parts  of  water  to  1  of  stock,  and 
then  gradually  increase  the  water  supply,  if  found  necessary. 

136.  Regulating  the  Suction. — If  the  stroke  of  the  shake  be  too 
long,  the  stock  will  wash  back  from  the  deckle  straps,  thinning 
the  edges  and  causing  a  mark  about  2  or  3  inches  from  the  edge 
of  either  side.  Search  between  the  slices  and  deckle  straps  for 
causes  of  feathery  edges;  these  may  result  from  striking  of  the 


§6  THE  MODERN  PAPER  MACHINE  85 

deckle  straps  against  the  slices.     See  that  deckle  straps  have 
clean,  square  edges,  and  that  they  rest  flat  on  the  wire. 

There  should  be  a  sufficient  number  of  suction  boxes  on  the 
machine  to  keep  too  much  water  from  getting  over  to  the  couch 
rolls.  It  is  well  to  use  only  about  7  inches  of  vacuum  on  all  the 
boxes;  but  if  there  are  not  enough  boxes,  a  greater  vacuum  must 
be  used,  in  order  to  do  the  work.  Bear  in  mind,  however,  that 
when  10  inches  or  more  of  vacuum  is  used,  the  life  of  the  wire  will 
be  shortened.  There  should  be  at  least  4  suction  boxes.  Too 
much  suction  on  the  boxes  will  sometimes  prove  to  be  an  excessive 
load,  and  cause  the  lower  couch  roll  to  slip  on  the  wire.  If  the 
box  covers  are  of  wood,  see  that  the}'  are  planed  smooth,  so  the 
wire  will  not  be  forced  to  follow  the  ridges  it  makes  in  the  covers ; 
also  see  that  the  box  covers  are  thick  enough  to  keep  them  from 
vibrating  when  a  strong  suction  is  carried. 

137.  Froth. — When  making  soft-sized  paper,  froth  is  liable 
to  cause  trouble;  in  such  case,  lower  the  slices  and  use  more 
water,  so  the  froth  is  kept  back  of  the  slices.  Small  bubbles 
sometimes  escape  down  the  edge  along  the  deckle  straps;  this 
may  be  prevented  by  using  a  piece  of  paper,  folded  where  the 
straps  and  slices  meet.  The  bubbles  that  gather  on  the  edge 
of  a  laid  dandy  roll  can  be  kept  away  by  rubbing  a  little  oil  on  the 
dand}',  just  off  from  the  edge  of  the  paper,  or  by  oil  ng  the  wiper 
cloth,  just  over  the  edge.  Do  not  spend  money  on  patented 
froth-killing  mixtures.  A  good  formula  is  a  mixture  of  lin- 
seed oil  and  bleach,  half  and  half  (1  to  1),  with  about  a  pint  of 
turpentine  added  to  every  5  gallons  of  the  mixture. 

138,  Kerosene  is  also  a  good  froth  killer.  Either  kerosene 
or  the  mixture  just  mentioned  can  be  advantageously  used  by 
suspending  it  in  a  o-gallon  can  over  the  suction  of  the  white- 
water  pump.  The  drip  of  the  froth  killer  should  be  at  the  rate 
of  about  5  or  6  drops  per  minute.  This  can  be  controlled  either 
by  soldering  a  small  radiator  valve  to  the  bottom  of  the  can  or 
simply  by  punching  a  small  hole  in  the  can  and  passing  some  lamp 
wick  through  it,  so  the  hole  can  be  plugged  entirely  by  the  lamp 
wick,  if  desired,  or  as  nearly  plugged  as  is  necessary.  Some- 
times this  froth-killing  mixture  is  dumped  into  the  beaers  before 
emptying  them ;  about  |  pint  of  the  mixture  to  a  1 200-pound  beater 
is  sufficient.  A  good  spray,  preferably  rotating  or  oscillating,  over 
the  pond  or  over  the  flow  box  is  usually  very  helpful. 


86  PAPER-MAKING  MACHINES  §0 

To  keep  the  dandy  roll  free  from  froth  when  making  laid 
papers  at  high  speed,  place  a  perforated  pipe  in  front  of  it,  so  a 
little  steam  may  be  blown  across  the  surface;  this  will  keep  it 
clean. 

139.  Enlarging  the  Watermark. — Sometimes  it  is  necessary  to 
have  the  watermark  in  the  paper  slightly  larger  than  the  size  of 
the  marks,  or  the  distance  between  them  in  the  paper  must  be 
slightly  greater  than  the  spaces  on  the  dandy  roll;  in  such  cases, 
either  the  mark  must  be  stretched  or  the  paper  must  be  stretched. 
First  let  the  wiper  cloth  bear  sufficiently  hard  on  the  dandy  to 
slow  it  up;  not  so  hard  as  to  cloud  the  mark,  but  just  enough 
to  gain  a  little.  Then  speed  up  the  first  press  somewhat,  to  get 
a  little  more  stretch,  and  do  the  same  at  the  second  press.  In 
this  manner,  a  dandy  mark  may  be  stretched  a  full  eighth  of  an 
inch. 

Lack  of  uniformity  in  the  dandy  marks  across  the  machine,  if 
the  dandy  is  straight,  is  probably  due  to  improper  crowning  of 
the  press  rolls,  which  makes  the  paper  either  wetter  at  the  ends 
than  in  the  middle  or  the  reverse  of  this.  When  the  paper  is  not 
uniformly  pressed,  the  wetter  parts  are  stretched  more  on  the 
dryers  than  the  drier  parts.  When  setting  a  dandy,  be  careful 
that  the  deckles  and  markings  are  right ;  that  is,  set  it  so  that  the 
edges  of  the  paper  come  the  proper  distance  from  the  marks. 
Count  the  circumferential  bars  on  the  dandy,  from  the  edge  of 
the  paper  to  the  mark,  and  make  the  number  equal  on  both 
sides. 


THE  COUCH-ROLL  JACKET 

140.  The  Couch  Roll. — Be  certain  that  the  upper  couch  roll 
is  not  couched  too  much;  in  other  words,  be  sure  that  the  weight 
of  the  upper  couch  roll  is  carried  entirely  by  the  lower  couch  roll, 
and  that  no  part  of  its  weight  is  carried  by  the  wire. 

In  a  perforated  roll,  the  holes  keep  water  and  wool  balls  from 
collecting  under  the  jacket,  and  thus  causing  the  jacket  to  creep 
and  move  around  the  roll.  These  holes  may  convey  quite  a  Httle 
water  into  the  inside  of  the  upper  couch  roll,  the  water  being 
squeezed  out  by  the  nip  between  the  rolls  or  by  the  squeeze 
action  of  the  guard  board.  This  water  is  drained  out  of  holes 
in  the  head  of  the  roll,  and  is  led  away.  An  old  upper  couch 
roll  M'ill,  in  time,  accumulate  enough  slime  and  refuse  on  its 


§6  THE  MODERN  PAPER  MACHINE  87 

inside,  from  these  holes,  to  cause  trouble  by  getting  the  jacket 
spotted,  and  so  dirtying  the  paper.  Although  this  rarely 
happens,  it  is  sometimes  a  cause  of  trouble,  one  that  a  paper 
maker  might  not  think  of,  unless  it  had  occurred  in  his  previous 
experience. 

141.  Putting  on  a  New  Jacket. — ^When  putting  a  new  jacket 
on  the  couch  roll,  have  a  jacket  of  the  right  size  for  the  machine 
and  of  the  right  character  for  the  kind  of  paper  to  be  made.  The 
felt  maker  should  be  given  full  information  as  to  the  requirements 
to  be  met,  and  he  should  also  be  fully  informed  regarding  any 
defects  in  the  jacket  and  of  any  difficulties  encountered  while 
the  jacket  is  in  use. 


-T 


Fig.  47. 

The  old  jacket  is  cut  lengthwise,  and  the  wire  is  driven  forward 
until  the  jacket  is  clear.  The  new  jacket  is  opened  on  the  clean 
machine  floor  and  carefully  measured.  Should  it  appear  a  trifle 
small,  it  can  be  stretched  a  little  on  a  stretcher,  such  as  is  shown 
in  Fig.  47.  The  hard-maple  beams  A,  rounded  on  the  outside, 
over  which  the  jacket  is  stretched,  are  supported  clear  of  the 
floor,  and  they  are  pushed  apart  by  the  toggle  joints  T,  by  turning 
the  nut  N  against  the  yoke  Y.  This  can  be  done  while  the  upper 
couch  roll  is  being  prepared.  There  are  several  designs  of  jacket 
stretchers. 

When  the  ends  of  the  jacket  are  held  tight  by  clamping  rings, 
screwed  or  bolted  against  the  end  of  the  roll,  or  if  the  jacket  is 
sewed  fast,  each  end  is  punched,  about  3  inches  from  the  edge, 
with  a  row  of  j-inch  holes,  about  6  inches  apart,  and  threaded 
with  stout  twine. 

Take  off  the  shower  pipe  and  guard  board,  or  lift  it  clear; 
also,  the  guard  rail,  if  there  be  one.  Remove  weights  and  levers, 
and  lift  the  upper  couch  roll  well  clear  of  the  lower  roll  and  the 
wire.  Be  very  careful  not  to  walk  on  the  wire  or  drop  anything 
on  it.     Clean  the  roll  thoroughly,  inside  and  out.     To  prevent 


88  PAPER-MAKING  MACHINES  §6 

sweating  of  the  roll,  pour  a  few  pailfuls  of  hot  water  on  it,  and 
wipe  it  dry  just  before  putting  on  the  new  jacket. 

SHp  the  new  jacket  over  the  lifting  or  porter  bar  used  for 
putting  on  the  wire,  making  sure  that  the  nap  shall  be  smoothed 
down  as  the  jacket  runs  under  the  guard  board;  fit  the  open  end 
of  the  bar  over  the  extension  of  the  upper  couch-roll  journal, 
on  the  front  side,  and  hft  the  free  end  with  the  chain  hoist. 
When  the  weight  on  the  bearing  is  relieved,  remove  the  bearing 
cap,  and  swing  the  bell-crank  lever  out  of  the  way. 

142.  Couch-Roll  Jackets. — The  couch  roll  on  a  Fourdrinier 
serves  two  main  purposes:  the  first  is  to  transfer  the  paper  from 
the  Fourdrinier  wire  to  the  felt ;  the  second  is  to  squeeze  out  as 
much  water  as  possible  in  the  process.  Consequently,  in  order 
to  withstand  this  great  pressure,  the  jacket  must  be  very  strong 
and  firm;  if  it  does  not  have  the  proper  strength,  this  pressure 
causes  it  to  become  loose  and  to  get  baggy  on  the  roll. 

The  older  practice  was  to  use  a  jacket  on  both  top  and  bottom 
rolls,  and  this  practice  is  still  carried  out  in  a  few  mills  making 
very  high-grade  paper  at  slow  speeds.  At  the  present  time, 
however,  in  most  mills  where  jackets  are  used,  only  the  top  roll 
is  jacketed. 

Couch-roll  jackets  are  woven  in  tubular  form;  this  necessarily 
makes  the  production  slow,  since  a  great  many  threads  must  be 
woven  to  a  single  inch  in  a  loom.  These  tubes  are  in  lengths 
sufiicient  to  allow  several  jackets  of  the  same  diameter  to  be  cut 
from  one  tube,  when  finished. 

When  finishing  jackets,  all  sizes  are  pulled  to  a  diameter  some- 
what smaller  than  the  diameter  of  the  roll  on  which  they  are  to 
be  used.  They  are  stretched  while  wet  to  a  size  that  allows 
them  to  be  slipped  over  the  roll;  and  after  they  have  been  dried 
on  the  stretchers,  this  size  is  held  until  they  are  again  wet  up  on 
the  paper  machine.  When  the  water  strikes  the  jacket,  it 
tends  to  shrink  back  to  its  former  size,  thereby  hugging  the 
couch  roll  tightly. 

The  guard  board  has  more  to  do  with  the  length  of  service 
received  from  a  jacket  than  any  other  one  thing,  since  undue 
pressure  on  the  guard  board  causes  the  jacket  to  wear  very 
rapidly,  and  it  has  a  tendency  to  make  the  jacket  become  loose 
and  get  lumpy  on  the  roll.  Guard  boards  should  have  a  beveled 
edge  and  should  be  kept  in  good  condition.  If  the  jacket  be 
shrunk  on  evenly  and  firmly  at  the  start,  and  if  proper  care  be 


§6  THE  MODERN  PAPER  MACHINE  89 

exercised  regarding  the  pressure  applied  to  the  guard  board, 
good  results  can  usually  be  obtained.  In  late  years,  many  of  the 
news  mills  have  been  obliged  to  use  a  considerable  percentage 
of  jack  pine  in  the  manufacture  of  their  paper,  the  pitch  from 
which  often  accumulates  on  the  jacket.  If  this  pitch  is  not 
washed  off  with  proper  care,  the  life  of  the  jacket  is  often  very 
materially  reduced. 

Now  with  everything  clean  and  clear,  carefully  draw  the  jacket 
over  the  roll  until  it  overlaps  the  same  distance  on  either  side. 
Replace  front  bearings  and  remove  lifting  bar;  draw  up  quickly 
and  strongly  on  the  twine  threaded  into  either  end,  avoiding 
wrinkles,  and  tie  in  a  knot  that  will  not  slip.  Another  method 
of  fastening  the  ends  is  described  in  Art.  143.  Lower  the  roll 
until  it  makes  firm  contact  with  the  lower  roll;  and  if  a  clamp  be 
used  to  hold  the  jacket,  screw  or  bolt  it  firmly  in  place. 

143.  Couch-roll  jackets  get  worn  more  quickly  at  the  edges 
when  the  ends  are  so  fastened  to  the  head  of  the  roll  that  the 
jacket  is  held  at  these  points,  although  it  may  slip  at  the  center. 

Couch-roll  jackets  are  often  fastened    __^ j 

by  sewing  crisscross,  across  the  heads, 
with  stout  packing  thread,  A  better 
method   of   fastening  the   ends  is  to 

make  a  wood  disk,  Fig.  48,  shaped    ' 

on  its  edge  like  a  frustum  of  a  cone,  ^^°"  ^^' 

to  which  the  ends  of  the  jacket  are  fastened  with  copper  nails. 
This  ring  is  not  fast  at  the  roll;  so  if  the  jacket  slips  a  bit,  the 
ring  turns  with  it,  and  the  jacket  is  not  strained.  Couch-roll 
jackets  that  are  clamped  to  the  couch-roll  heads  with  bolted 
metal  plates  do  not  last  long. 

Having  fastened  the  jacket,  replace  shower  pipe,  guard  roll, 
and  guard  board,  the  edge  of  the  latter  having  been  planed  to  a 
true  straight  edge  by  the  millwright. 

144.  Shrinking  the  Jacket. — The  jacket  must  now  be  shrunk, 
to  grip  the  roll  tightl}^;  this  is  accomplished  by  pouring  several 
pails  of  very  hot  water  across  the  roll  ver}^  quickh^;  then  start 
the  wire,  to  turn  the  roll  and  enable  any  dry  places  on  it  to  be 
wetted.  When  the  jacket  is  firmly  set,  check  further  shrinking 
by  starting  the  cold-water  shower.  Lower  the  guard  board 
carefully,  and  set  its  edge  so  the  jacket  will  be  uniformly  dry  for 
its  full  length;  use  as  little  pressure  as  possible. 


90  PAPER-MAKING  MACHINES  §6 

145.  Starting  a  New  Jacket. — AVhen  starting  a  new  jacket  on 
fine  stock  that  is  liable  to  stick  to  the  nap.  use  as  little  weight  on 
the  roll  as  possible,  and  put  the  guard  board  down  fairlj^  tight. 
Before  starting,  pour  a  few  handfulls  of  white  clay  or  filler  on  the 
jacket,  while  dry,  so  the  nap  may  be  flattened  and  the  jacket 
made  harder  by  closing  the  pores  with  the  clay  or  filler;  or  use  a 
solution  of  soda  ash  in  boiling  water  for  the  same  purpose. 
When  starting  the  roll,  no  water  should  be  run  on  the  roll,  but 
a  little  clay  may  be  put  on  it.  When  the  shower  on  the  working 
edge  of  the  guard  board  is  turned  on,  the  pipe  should  be  so  turned 
that  the  jets  will  play  on  the  front  of  the  guard  board,  the  water 
running  down  the  front  onto  the  jacket.  If  the  jets  play  on  the 
new  jacket,  the  nap  will  rise,  and  the  liabihty  of  -picking  up  the 
paper  will  be  much  greater.  But  if  the  paper  should  pick  up,  a 
little  turpentine  or  rosin  size  poured  on  the  jacket  will  stop  this. 

146.  Jacket  Troubles. — A  new  jacket  often  causes  trouble 
when  colored  papers  are  being  made,  since  the  picking  up  of 
fibers  causes  marks  on  the  surface  of  the  paper.  If  the  guard 
board  allows  water  to  pass,  the  jacket  will  pick  up  stock  as  it 
runs  onto  the  wire.  Brushes  that  have  been  weighted  with  lead 
and  placed  on  the  jacket  in  front  of  the  guard  board,  will  keep 
the  jacket  clean;  or  the  trouble  may  often  be  obviated  b}^  a 
vigorous  rubbing  by  hand.  For  brushing  jackets  and  felts,  a 
brush  of  fine  brass  wire,  or  a  piece  of  woolen-mill  card,  may  be 
used.  Turpentine  is  good  for  cleaning  the  edges  of  the  couch 
roll;  here  the  picking  up  is  w'orst,  which  may  be  due  to  the  dams 
in  the  suction  boxes  being  too  far  from  the  edge  of  the  paper. 

147.  If  the  jacket  seam  is  not  straight,  that  is,  if  it  tends  to  lie 
diagonally  across  the  wire,  it  may  be  straightened  by  increasing 
the  couch-roll  weights  on  the  side  where  the  seam  is  traveling 
ahead;  this  will  produce  a  drag  on  this  side  of  the  wire,  which  will 
straighten  the  seam.  Adding  weight  in  this  manner  may,  how- 
ever, cause  lumps  of  wool  to  gather  inside  of  the  jacket,  and  it 
may  also  make  the  paper  thinner  on  one  side;  it  is  not  the  best 
practice  to  have  the  weights  uneven  to  any  extent. 

The  machine  tender  should  be  careful  not  to  allow  the  upper 
couch-roll  jacket  to  slip  or  twist.  Should  this  occur,  reduce  the 
pressure  of  the  guard  board  as  much  as  possible  and  adjust 
weights  on  the  upper  couch  roll,  by  easing  up  on  the  side  that 
begins  to  lag  behind.     If  the  jacket  gets  so  loose  at  the  center  that 


§6  THE  MODERN  PAPER  MACHINE  91 

it  wrinkles  because  of  a  crown  on  the  lower  roll,  take  off  the  guard 
board  and  end  clamp,  and  stretch  the  jacket  into  place. 

When  using  a  pressure  roll,  watch  the  lower  couch  roll;  if 
there  is  too  much  suction  on  the  boxes,  the  lower  couch  roll  will 
slip  in  the  wire. 

148.  A  Patented  Jacket. — Most  jackets  are  woven  endless 
tubes  of  high-grade  wool,  usually  hard  but  fine.  An  English 
jacket  that  finds  considerable  favor  is  felted  instead  of  being 
woven;  it  therefore  has  no  warp,  and  it  is  the  same  all  through  and 
in  all  directions.  Special  care  must  be  taken  not  to  pull  or 
wrinkle  these  jackets,  with  the  guard  board  or  otherwise. 


THE  SUCTION  COUCH  ROLL  AND  SUCTION  BOXES 

149.  Amount  of  Suction.^ — As  previously  stated,  some  machines 
have  pressure  couch  rolls,  while  others  have  suction  rolls.  In  the 
case  of  a  suction  roll,  the  operator  must  be  careful  not  to  get 
too  much  suction  in  the  suction  boxes;  for,  if  this  occur,  it  will 
cause  the  wire  to  be  slack  after  leaving  the  suction  roll,  and  the 
wire  will  wrinkle.  The  best  way  to  determine  how  much  suction 
to  use  is  to  watch  the  wire  after  it  passes  the  suction  roll;  if  the 
wire  gets  slack,  reduce  the  suction  on  the  boxes  until  the  slack 
wire  below  draws  tight  enough  to  run  safely  without  wi'inkling. 
On  free  stock,  such  as  news,  cheap  tablet,  catalog,  wrapping, 
etc.,  it  is  practically  impossible  to  get  too  much  suction,  because 
air  penetrates  the  sheet  easily. 

150.  Braking  Efifects. — The  action  of  the  suction  boxes  in 
drawing  the  wire  down  to  the  surface  of  the  box,  results  in  a 
brake  effect  on  the  wire.  The  greater  the  suction  the  greater 
this  brake  effect,  which  must  be  overcome  by  an  added  pull  by 
the  surface  of  the  lower  couch  or  suction  roll,  to  drag  the  wire 
away  from  the  suction  boxes.  The  couch  roll  will  sometimes  slip 
under  the  wire,  if  the  load  it  pulls  is  too  great;  this  may  break  the 
paper  on  the  machine,  because  of  a  momentary  variation  in  the 
speed  of  the  wire,  unless  the  machine  be  driven  by  a  sectional 
electric  drive.  The  doctors  on  the  breast  roll  and  other  rolls  can 
also  act  as  brakes.  Anything  that  the  machine  tender  can  do  to 
reduce  the  amount  of  pull  on  the  wire  by  the  couch  roll,  without 
spoiling  the  paper-making  function,  will  increase  the  life  of  the 
wire. 


92  PAPER-MAKING  MACHINES  §6 

151.  Making  the  Wire  Run  True. — If.  the  machine  tender  find 
that  the  wire  guide  will  not  keep  the  wire  true,  and  the  wire 
tends  to  travel  to  one  side,  then,  provided  the  rolls  of  the  machine 
are  square,  the  trouble  may  be  in  the  suction  boxes.  The  wire 
will  wear  grooves  in  the  suction-box  covers,  and  sometimes  the 
wire  jumps  the  grooves,  which  causes  it  to  be  led  to  one  side. 
When  this  occurs,  the  guides  cannot  help  matters;  the  only 
remedy  is  to  cut  off  the  vacuum,  by  shoving  in  the  rods,  slacking 
the  supporting  bolts,  and  moving  the  box  so  the  wire  will  not  enter 
the  same  grooves.  However,  it  is  better,  if  possible,  to  take  out 
the  boxes  and  plane  the  covers. 


MISCELLANEOUS 

152.  The  Showers. — The  patented  shower  pipes  use  less  water 
per  minute  and,  at  the  same  time,  throw  a  stronger  stream;  that 
is,  a  shower  pipe  that  has  had  some  thought  expended  on  its 
design  is  not  only  more  economical  of  water  but  it  also  does  its 
work  better.  A  rough  figure  that  is  approximately  correct  for  the 
old-fashioned  shower  pipes,  operating  under  35  pounds  water 
pressure,  is  1|  gallons  of  water  per  minute  per  inch  of  width  of 
machine;  the  modern,  patented  shower  pipes  will  save  about  one- 
third  of  this  water. 

If  the  shower  pipes  are  not  doing  good  cleaning  work,  increase 
the  water  pressure,  if  possible,  and  keep  the  holes  clear.  Use 
filtered  water.  The  effect  of  an  increase  of  water  pressure  on  the 
shower  pipes  is  to  increase  the  force  of  the  showers,  it  also 
increases  the  consumption  of  water.  For  instance,  a  48-hole,  old- 
fashioned  shower  pipe,  1|  inches  in  diameter,  with  iV,-inch  holes, 
spaced  |  inch  between  centers,  showed  the  following  water 
consumption : 

At  10  pounds  pressure,  13.3  gallons  per  minute 
At  20  pounds  pressure,  15.5  gallons  per  minute 
At  30  pounds  pressure,  18.2  gallons  per  minute 
At  40  pounds  pressure,  21.6  gallons  per  minute 
At  50  pounds  pressure,  25.0  gallons  per  minute 

In  selecting  the  spray  pipe,  the  nozzles  that  give  the  finest 
spray,  and  which  throw  the  spray  so  it  falls  over  a  large  area  of 
froth,  should  be  selected.  These  pipes  are  generally  located 
over  the  flow  box,  over  the  apron,  and  just  back  of  the  slices, 
their  sole  duty  is  to  reduce  the  accumulation  of  froth. 


§6 


THE  MODERN  PAPER  MACHINE 


93 


153.  White    Water. — The     water    that  drains    through    the 
Fourdrinier  wire,  and  which  is  often  increased  in  volume  by 

S^ock  in  Stuff  Chesi) 
, (37%  -96  7o  Wafer  3%  -B 7o  Fiber)        


V 


Y 


A-t  Re,gu/ah'n/j  Box.  V/'aShffR/mp 


Ai'  Screens 


f 


(Same  as  Above) 

Wblh  Water  Added 


(39  7o-9S.S7o  Water) 
l7o-0S7o  Fiber 

\ 
At  Flow  Box 


(Same  as  Screens) 


I 


A-f-  Forming  Table 


(Same as  Flow  Box,  Loses  White  Wafer 
to  Save- Alls  Boxes,  Leaving  Sheet 
ofFbper  on  Wire) 


>< 


Y  White  Wafer  to  Fan  Pump 


> 


At  Suction  Boxes 
( About  937o  -967o  Wafer) 


Y 


Y  White  Wafer  to  ^ 

Fan  Pump  or  Fiber  Recovery 


Besh  Wafer  to  Fan  Pump- 


When  Needed 


At- Couch  Rolls 
(About  907o-927o  Wafer) 


Y         White  Water  to  Fiber  Recover,ij  or  to  Waste 


-> 


At  Wet  Press 


(About  857o  -907o  Wafer) 


Fig.  49. 


water  from  showers,  is  called  white  water,  back  water,  or 
re-water;  it  may  also  be  water  from  the  suction  boxes  and  couch 
rolls.     This  water  contains  considerable  fine  fiber  and  mineral 


94  PAPER-MAKING  MACHINES  §6 

matter.  Most  of  it  is  lifted  by  a  suction  pump,  and  is  used  to 
dilute  stock  passing  to  the  screens.  What  happens  to  the  water 
in  stock  at  the  wet  end  of  the  machine  is  shown  in  the  chart, 
Fig.  49.  It  is  to  be  observed  that  about  50%  of  the  water 
removed  at  the  Fourdrinier  part  leaves  the  paper  at  the  table 
rolls,  with  about  25%  taken  out  at  the  suction  boxes  and  25% 
at  the  couch  rolls;  this  leaves  still  90%  of  water  in  the  sheet 
going  to  the  presses.  Reference  should  be  made  to  the  diagram 
in  Art.  21. 

154.  Mesh  of  the  Wire. — By  mesh  is  meant  the  number  of 
wires  or  openings  to  the  inch.  The  wire  used  for  coarse  papers,  as 
news  or  wrapping,  is  ordinarily  60-  or  65-mesh;  for  writing  or 
book  papers,  it  is  generally  70-,  75-  or  80-mesh ;  while  for  special 
papers,  as  cigarette,  a  much  finer  mesh  is  required. 

The  alloy  used  for  weaving  Fourdrinier  wires  must  be  strong, 
tough,  and  flexible  enough  to  weave  into  a  flat  cloth,  and  must  be 
fairly  resistant  to  acids.  Extra  wires  are  used  at  the  edges,  to 
give  greater  strength  and  wearing  qualities.  An  alloy  commonly 
used  is  80%  copper  and  20%  zinc.  Phosphor-bronze  wires  are 
now  used  almost  exclusively  on  newsprint  machines. 

155.  Starting  the  Wire. — The  following  directions  for  starting  a 
new  wire  have  been  condensed  from  Witham's  "Modern  Pulp 
and  Paper  Making:" 

Great  care  must  be  exercised  in  starting  a  new  wire,  first  being 
assured  that  everything  is  in  proper  condition  before  striking  in 
the  clutch,  which  operation  should  be  performed  very  gently. 
A  clutch  should  never  grip  so  hard  that  the  wire  is  started  with  a 
jerk.  It  is  found  to  be  a  very  good  plan  to  turn  the  wire  around 
slowly,  at  least  once  or  twice,  before  the  couch  is  set  down,  thus 
getting  the  wire  in  proper  alinement  before  setting  up.  The 
stretch  roll  must  not  be  tightened  down  until  after  the  top  couch 
roll  is  lowered  into  place. 

The  seam  of  the  wire  should  be  watched  closely,  so  that  neither 
end  will  run  ahead  of  the  other,  but  shall  line  up  with  the  suction 
box  or  a  parallel  roll.  All  particles  of  hard  material  must  be 
brushed  and  rinsed  off  before  the  wire  is  started  up. 

If  for  anj'  reason  the  wire  is  stopped  and  the  stock  is  shut  off, 
the  shake  should  also  be  stopped,  since  there  is  danger  of  shaking 
the  wire  into  a  wrinkle  when  it  is  not  loaded  with  a  sheet  of  paper 
and  held  down  by  the  suction  boxes.     If  anything  happens  that 


§6  THE  MODERN  PAPER  MACHINE  95 

makes  it  necessary  to  strike  the  wire  out  immediately,  without 
first  having  a  chance  to  shut  off  the  stock,  such  stock  should  be 
thoroughly  rinsed  from  the  wire  before  attempting  to  start  again. 
The  weights  should  be  removed  from  the  couch  levers,  and,  by  all 
means,  the  suction  should  be  broken  where  the  stock  has  sealed 
the  wire  over  the  top  of  the  suction  boxes;  this  can  be  done  by 
rinsing,  or  by  rubbing  the  fingers  across  the  top,  to  break  the 
suction  by  letting  air  in. 

Care  should  be  taken  to  let  up  on  the  guard-board  screws  before 
striking  the  wire  in,  since  the  couch-roll  jacket  is  frequently  torn 
off  by  neglecting  to  do  this.  The  guard  board  should  never  be 
let  down  onto  the  jacket  until  after  the  weights  have  been  applied 
to  the  couch  rolls;  there  is  always  enough  slack  in  the  couch-roll 
boxes,  so  that  if  the  guard  board  is  let  down  before  the  weights 
are  apphed,  this  slack  is  taken  up  in  the  boxes,  and  the  guard 
board  will  necessarily  have  to  carry  the  weight  of  the  weights  on 
the  levers.  In  setting  the  guard  board,  great  care  should  be 
taken  to  lower  it  horizontally,  never  allowing  one  end  to  go  down 
before  the  other;  otherwise,  the  jackets  would  be  torn  from  the 
couch  roll. 

Stock  should  never  be  allowed  to  pile  up  high  enough  in  the 
save-all  to  touch  the  wire. 


PAPER-MAKING 
MACHINERY 

(PART  1) 


EXAMINATION  QUESTIONS 

(1)  Name  some  advantages  to  a  student  in  keeping  a  notebook. 
What  might  be  put  in  it? 

(2)  Name  the  principal  parts  of  a  Fourdrinier  paper  machine 
and  mention  briefly  the  function  of  each. 

(3)  Explain  fully  what  happens  to  the  stuff  in  the  stufT  chest 
until  it  reaches  the  paper  machine. 

(4)  What  is  the  other  function  of  the  water  used  to  carry  the 
paper  fiber  onto  the  wire? 

(5)  What  happens  to  the  paper  if  the  excess  water  is  not 
removed  before  the  paper  reaches  the  couch  rolls? 

(6)  Explain  a  cause,  and  mention  a  remedy  for  (a)  slime  spots, 
(h)  "fish  tails,"  (c)  thin  edges,  (d)  crushed  paper,  (e)  dandy 
marks. 

(7)  Describe  the  course  of  the  water  used  at  the  wet  end  of  a 
paper  machine. 

(8)  Name  some  points  3'ou  would  insist  on  in  ordering  a  stuff 
chest,  and  tell  why. 

(9)  Explain  the  purpose  of  the  regulating  box. 

(10)  What  is  the  characteristic  of  paper  pulp  on  which  the  auto- 
matic regulation  of  stuff  is  based? 

(11)  (a)  If  you  were  building  a  mill  would  3'ou  install  a  save- 
all?     Why?     \h)  What  kind  would  you  select?     Why? 

(12)  Explain  the  operation  and  advantage  of  (a)  a  flat  screen; 
(6)  a  rotary  screen. 

(13)  Tell  briefly  the  story  of  the  invention  and  development  of 
the  Fourdi'inier  machine. 

(14)  Where  are  the  following  parts  and  what  are  they  for: 
(a)  flow  box?  (6)  shake?  (c)  dandy  roll?  (d)  guard  board? 
§6  97 


98  PAPER-MAKING  MACHINES  §G 

(e)  apron?     (J)  deckle  straps?     {h)  guide  roll?     (z)  suction  box? 
(j)  stretch  roll?     (k)  slice? 

(15)  (a)  What  is  the  function  of  the  couch  press?  (6)  How 
is  this  accomplished  in  the  case  of  a  suction  couch  roll  as  com- 
pared with  the  ordinary  couch  press? 

(16)  Explain  the  action  of  table  rolls  in  the  removal  of  water 
from  the  paper. 

(17)  (a)  What  effects  are  produced  on  the  stock  by  raising  or 
lowering  the  breast  roll?     (6)  using  more  or  fewer  table  rolls? 

(18)  (a)  Why  is  it  necessary  to  have  rolls  square  with  the 
machine?     (6)  how  are  they  tested? 

(19)  What  is  the  difference  between  a  left-hand  and  a  right- 
hand  machine? 

(20)  How  is  the  paper  taken  from  the  wire  to  the  first  press 
felt? 


SECTION  6 

PAPER-MAKING 
MACHINES 


(PART  2) 


THE  PRESS  PART 


DE-WATERING  THE  PAPER 

156.  Passing  to  the  Press  Part. — At  this  point,  the  reader  is 
requested  to  turn  back  to  Art.  52,  where  the  cut  squirt  is  described 
and  also  the  method  of  passing  the  paper  by  hand  from  the  couch 
roll  to  the  wet  felt.  It  is  well  to  note  here  that  the  paper  can  be 
picked  off  the  wire  by  a  rough  felt  and  automatically  placed  on 
the  first  wet  felt.  This  small  auxiliary  felt  need  be  only  a  little 
wider  than  the  strip  of  paper  cut  by  the  cut  squirt;  it  may  be 
carried  on  two  or  three  rolls  in  a  frame  that  can  be  moved  to 
place  the  felt  in  contact  with  the  wire  and  the  first  press  felt. 
The  onl}^  necessary  condition  is  that  such  an  arrangement  be 
adjustable  and  removable;  also  that  the  small  felt  be  rougher  and 
more  porous  than  the  wet  felt.  The  paper  may  be  blown  from 
the  couch  roll  to  the  wet  felt,  that  is,  the  narrow,  squirt-cut  strip 
can  be  so  blown.  A  successful  method  of  accomplishing  this  is 
to  have  the  blowing  pipe  from  which  the  air  jets  strike  the  wire 
at  or  near  the  edges  of  the  narrow  strip  cut  by  the  squirt.  The 
paper  is  thus  lifted  down  from  the  wire,  and  its  momentum, 
aided  by  the  air  current,  carries  the  strip  across  to  the  first  felt. 
With  a  suction  couch  roll,  the  jet  of  compressed  air  may  be 
directed  from  within  the  roll. 

157.  De-watering  Devices. — Up  to  this  point,  the  paper  has 
been  de-watered  as  follows:  the  Fourdrinier  part  of  the  paper 
§6  99 


100 


PAPER-MAKING  MACHINES 


machine  partly  de-waters  the  paper  by  the  action  of  the  table 
rolls,  which  causes  the  water  to  drain  out  through  the  wire; 
when  this  process  has  gone  as  far  as  possible,  the  next  step  is  the 
use  of  suction  boxes,  which  suck  out  the  water;  the  dandy  roll 
smooths  the  surface  a  little,  and  when  the  paper  has  passed  over 
the  suction  boxes,  it  has  become  strong  enough  to  be  squeezed 
in  the  couch  rolls.  After  having  passed  through  the  couch 
rolls  or  over  the  suction  roll,  the  next  de-watering  device  is 
through  the  use  of  pressure;  and  as  the  paper  passes  from  the 
wire  to  the  wet  felt,  as  much  water  as  possible  is  squeezed  out 
in  the  presses. 

158.  Per  Cent  of  Stock  and  Water  at  Different  Stages.— The 
following  table  shows  the  per  cent  of  stock  and  water  at  various 
stages,  from  beaters  to  dryers: 


News 

Book 

All  sulphite 

(600  ft.  per 

(300  ft.  per 

(400  ft.  per 

min.) 

min.) 

min.) 

Solids 

Water 

Solids 

Water 

Solids 

Water 

Mixture  from  beater. 

3-3.5 

97-96.5 

4 

96 

4 

96 

Mixture  goipg  on  wire 

0.5-0.699.5-99.4 

1 

99 

1 

99 

Entering  couch  rolls . . 

10 

90 

8 

92 

12 

88 

Leaving  couch  rolls . . . 

131 

87 

17 

83 

25 

75 

Leaving  last  press .... 

26-30 

74-70 

29 

71 

40 

60 

Leaving  dryers 

91-97 

9-3 

91 

9 

93 

7 

1  It  is  claimed  that,  with  a  suction  roll,  the  solids  here  will  be  15%. 


Water  does  not  leave  book  paper  as  readily  as  it  leaves  news; 
hence,  book  paper  leaves  the  Fourdrinier  and  enters  the  dryer 
part  carrying  a  greater  per  cent  of  water  than  news  does.  The 
per  cent  of  stock  on  book  paper  will  be  approximately  the  same  as 
on  papers  where  bleached  sulphite  stock  is  used.  Water  leaves 
paper  made  of  unbleached  sulphite  more  readily  than  from  any 
other  that  has  had  the  same  preparatory  treatment;  therefore, 
more  water  can  be  pressed  out  by  the  couch  action  and  also  by  the 
presses,  the  felts  do  not  fill  so  easily,  and  a  greater  pressure  can 
be  applied  on  rolls.  This  grade  of  sulphite  paper  leaves  the 
presses  dryer  than  either  news  or  book  papers. 


§6 


THE  PRESS  PART 


101 


159.  Referring  to  the  sulphite  part  of  the  table,  it  is  apparent 
that  if  the  ratio  of  solids  to  water  at  the  breast-roll  end  of  the  wire 
is  1  to  99,  then  it  will  take  9900  pounds  of  water  to  make  100 
pounds  of  paper.  In  practice,  somewhat  less  water  is  required, 
because  the  paper  leaving  the 
machine  is  not  bone  dry;  it  still 
contains  about  7%  of  water.  In 
calculating  the  amount  of  water 
necessary  for  the  machine,  there 
should  be  added  the  amount  of 
water  required  for  showers  and 
washing;  and  there  should  be  sub- 
tracted from  the  total  initial  supply 
of  pure  water  estimated  as  necessary 
the  amount  of  white  water  returned 
through  the  save-alls,  fan  pump,  and 
screens. 


DESCRIPTION  OF  PRESS  PART 

160.  Purpose  and  Limitations.— 
The  press  part  consists  of  a  series 
of  press  rolls,  through  which  the 
paper  passes.  The  object  of  these 
presses  is  to  squeeze  out  of  the  paper 
as  much  water  as  possible,  without 
injur}'-  to  the  paper.  While  it  is 
cheaper  to  remove  the  water  by 
pressure  rather  than  b}'  evapora- 
tion, up  to  a  certain  limit,  it  is 
practically  impossible  to  dry  paper 
or  pulp  by  mechanical  pressure  be- 
yond the  point  where  it  has  less 
than  60%  of  contained  water;  in 
fact,  it  is  very  unusual  to  find  a 
press  part  on  a  paper  machine 
that  deHvers  paper  at  the  dryer 
end  containing  less  than  66%  water,  the  remaining  34%  being 
paper  stock. 

161.  Course  of  the  Paper. — The  paper  in  the  press  part  is 
convej-ed  on  felts  through  the  nip  of  the  presses.     The  lower  rolls. 


102  PAPER-MAKING  MACHINES  §6 

unless  suction  rolls,  of  the  presses  are  rubber  covered,  and  the 
upper  rolls  are  made  of  hardwood  or  stone,  cast  iron  or  have  a 
bronze  outside  casing.  Fig.  50  shows  a  press  part  for  high-speed 
news,  which  consists  of  three  presses,  the  paper  being  reversed 
on  the  third  press.  Where  only  two  presses  are  used,  the  paper 
is  reversed  at  the  second  press. 

The  machine  tender  passes  the  paper  from  the  couch  roll  V 
onto  the  felt  of  the  first  press  at  roll  U;  the  felt  carries  the  paper 
over  the  suction  box  Bi;  from  thence,  it  travels  over  a  felt  roll 
that  is  so  placed  that  the  felt  and  paper  run  down  toward  the 
nip  of  the  first  pair  of  press  rolls  Ki  and  Ko.  This  arrangement 
keeps  the  water  that  is  squeezed  out  Ijy  the  press  rolls  from 
running  onto  the  incoming  felt  and  paper,  since  it  is  thereby 
forced  to  run  down  the  near  side  of  the  lower  press  roll.  This 
position  of  the  felt  roll  also  keeps  air  from  being  pocketed  between 
the  paper  and  the  felt.  The  platforms  P  and  Pi  allow  the 
machine  tenders  to  cross  the  machine. 

162.  As  the  paper  passes  through  the  first  press,  it  leaves  the 
felt  and  clings  to  the  first  upper  press  roll  until  it  reaches  the 
doctor  Di,  by  which  it  is  scraped  off  and  where  it  accumulates  as 
wet  broke  in  an  inchned  V-shaped  trough,  which  is  formed  by  the 
doctor  blade  and  the  back  retainer  wall  that  is  built  onto  the  doctor. 
This  broke,  or  waste  paper,  is  sent  back  to  the  beater  room. 

The  bottom  roll  of  the  first  press  is  covered  with  rubber;  the 
upper  press  roll  is  of  wood  (maple),  cast  iron,  cast  iron  with  a  brass 
sleeve,  or  stone  (polished  granite),  the  brass  sleeve  and  stone  rolls 
giving  the  best  surfaces  for  enabling  the  paper  maker  to  skin  the 
paper  off  the  upper  press  roll  before  lajdng  it  on  the  felt.  The 
felt  carries  it  forward,  and  it  is  passed  bj^  the  machine  tender 
from  roll  Ei  to  roll  E2,  on  its  way  to  the  second  press. 

When  the  machine  is  provided  with  a  cut  squirt,  this  is  set  to 
give  a  strip  from  3  to  6  inches  wide.  This  is  peeled  off  the  upper 
press  roll  bj^  picking  the  edge  with  thumb  or  finger  nails,  or 
blowing  it  off  b}^  compressed  air;  sometimes  it  is  laid  over  a  small 
roll,  and  placed  on  the  felt,  against  which  it  is  held  until  the 
drag  of  the  felt  is  sufficient  to  pull  the  paper  from  the  roll.  It 
is  fed  into  the  nip  of  the  second  press  and  the  cut  squirt  pushed 
across  the  wire.  Sometimes  this  strip,  widened  to  8  to  10  inches, 
is  carried  well  over  the  dryers  before  the  full  tail  is  cut. 

If  a  cut  squirt  is  not  used,  the  machine  tender  gets  as  much 
as  he  can  pull  away  from  the  front  edge,  then  the  back  tender 


§6  THE  PRESS  PART  103 

peels  the  remainder  gradually  away  until  the  paper  is  all  on  the 
felt.     A  prolific  cause  of  profanity! 

After  leaving  roll  Ei,  the  felt  passes  around  felt  rolls  Fi,  F2, 
Fz  to  stretch  roll  C\',  then  over  guide  roll  G\,  to  felt  roll  Fa,  under 
shower  pipe  J\,  past  whipper  Ti,  to  roll  U.  The  course  of  the 
other  felts  may  be  ti-aced  similarly.  In  Fig.  50,  the  felts  are 
indicated  by  full  lines,  and  the  paper  is  indicated  by  dotted 
lines. 

The  doctor  Di,  etc.  is  liable  to  scrape  grooves  into  the  upper 
roll;  for  this  reason,  it  is  supplied  in  many  cases  with  a  vibrating 
mechanism,  which  will  be  described  later. 

163.  Course  of  Press  Felts. — Before  leaving  the  first  press 
and  following  the  course  of  the  paper,  observe  how  the  first-press 
felt  gets  back  to  the  first  receiving  roll.  The  first-press  felt  is  a 
long  one,  and  the  extra  length  is  sometimes  carried  to  a  roll  in 
the  basement.  The  first  felt  must  be  of  rather  open  weave,  to 
allow  the  large  quantity  of  water  that  is  squeezed  out  at  the  first 
press  to  pass  through  it.  The  second  felt  is  generally  finer  than 
the  first  felt,  that  is,  it  is  softer  and  has  more  nap,  so  as  to  produce 
a  smoother  finish  on  the  paper  as  it  passes  through  the  nip  of 
the  press  roll.  According  to  the  kind  of  paper  being  made  and  the 
treatment  that  the  felt  receives,  the  first  felt  becomes  hard  in  the 
course  of  a  few  weeks,  or  even  sooner.  The  pores  are  filled  with 
filler  that  will  not  wash  out,  or  the  pores  are  forced  to  assume 
diamond  shapes  by  the  irregular  stretch  of  the  felt;  as  a  con- 
sequence, it  is  usually  necessary  to  remove  the  felt  before  it  is 
worn  out.  But  such  a  first  felt  is  still  good  enough  to  use  on  the 
second  press.  For  this  reason,  it  is  the  general  practice  on  news 
machines  so  to  design  the  first-press  part  that  the  felts  used  on  it 
are  of  the  same  length  as  those  on  the  second  press.  In  the 
design  shown  in  Fig.  50,  the  felt  on  the  second  press  is  long, 
because  the  paper  is  reversed  at  the  third  press,  and  this  necessi- 
tates that  the  second-press  felt  travel  the  full  distance  under  the 
third  press.  The  felt  stretcher  Ci  is  actuated  by  the  hand  wheel 
Hi,  by  means  of  a  sprocket  chain  and  two  sprocket  wheels,  in  a 
manner  to  be  described  later. 

It  should  be  noted  that  some  felt  rolls  have  the  felt  lapped 
around  them,  so  they  may  have  two  portions  of  felts  pulling  on 
them  in  the  same  direction;  it  is  evident  that  such  rolls  have  a 
greater  pull  exerted  on  them  by  the  felt  than  those  which  the 
felt  simply  passes  over.     The  latter  rolls  do  not  need  to  be  as 


125 

150 

175 

200 

225 

250 

7i-8 

81-9 

9F10 

10^-11 

lU-12 

12^-13 

lU 

lis 

2  A 

2,'a 

2!a 

2U 

104  PAPER-MAKING  MACHINES  §6 

large  or  as  strong  as  those  having  the  felt  wrapped  half  way 
around  them. 

164.  Size  of  Felt  Rolls. — The  usual  sizes  of  felt  rolls  and  their 
journals  for  different  widths  of  machines  are  given  in  the  following 
table,  all  dimensions  being  in  inches: 

Width  of  machine 100 

Sizes  of  rolls 6^-7 

Sizes  of  j  ournals 1 1's 

165.  Course  of  Paper  (Continued). — The  machine  tender,  or 
the  back  tender,  passes  the  paper  from  the  first-press  felt,  as  the 
felt  turns  down  on  felt  roll  Ei,  to  the  second-press  felt,  as  it 
turns  up  on  felt  roll  E2.  The  paper  is  carried  by  the  second-press 
felt  over  the  felt  suction  box  B2  (not  always  used),  and  over  the 
felt  roll,  which  is  raised  above  the  nip  of  the  second  press,  in 
exactly  the  same  manner  as  it  passes  to  the  first  press.  The 
doctor,  the  press  housing  and  arm,  the  weights  and  levers,  the 
stretcher  roll  C2,  and  the  guide  roll  G2,  are  the  same  in  all  respects 
as  those  of  the  first  press;  the  course  of  the  felt,  however,  is 
different,  as  will  be  seen  from  the  illustration. 

The  paper  is  to  be  reversed  at  the  third  press,  in  order  to 
bring  the  wire  side  against  the  upper  third-press  roll,  so  the 
impressions  of  the  wire  may  be  removed  by  the  smooth  surface 
of  the  upper  third-press  roll.  To  carry  the  paper  far  enough 
forward  in  the  machine  to  allow  of  its  return  in  the  reverse 
direction  through  the  third  press,  it  is  necessary  to  make  the 
second -press  felt  carry  the  paper  to  roll  E3.  The  machine  tender 
takes  the  paper  from  the  second-press  felt  at  roll  E3,  passes  it 
over  paper  rolls  Mi  and  M2,  and  places  it  on  the  third-press  felt 
at  roll  N.  If  the  paper  were  to  pass  direct  to  roll  N,  it  would 
break.  The  paper  rolls  Mi  and  M2  give  the  paper  plenty  of 
slack  and  allow  enough  give  and  take  in  the  pull  of  the  third- 
press  felt  to  permit  the  paper  to  be  laid  on  this  felt  without 
undue  strain,  with  its  consequent  breaks,  since  the  narrow  tail  of 
wet  paper  is  very  weak. 

At  the  third  press,  the  paper  enters  the  nip  of  the  press  rolls 
from  a  felt  roll  whose  top  is  higher  than  the  nip.  The  paper  is 
carried  around  by  the  face  of  the  upper  press  roll  in  the  third  press 
in  exactly  the  same  manner  as  in  the  other  two  presses,  because 
it  sticks  to  the  surface  of  the  roll  until  it  is  scraped  off  by  the 


§6  THE  PRESS  PART  105 

doctor  D3,  where  it  forms  wet  broke.  The  tail  is  skinned  off  the 
press  roll  by  the  machine  tender,  who  passes  it  over  the  paper 
roll  M3,  which  is  so  supported  by  brackets  that  it  is  higher  than 
the  top  of  the  upper  press  roll.  From  this  point,  the  paper  is 
passed  over  to  the  dryers.  Skinning  the  narrow  strip  of  paper 
from  the  roll  requires  skill  and  practice.  Unless  the  machine 
is  provided  with  compressed  air  nozzles,  the  edge  is  broken  by 
the  finger  nail,  quickly  torn  across,  then  pulled  away,  and  the 
strip  carried  forward,  over  the  paper-carrying  rolls,  and  passed 
to  the  smoothing  press  or  the  first  dryer. 

If  the  machine  has  no  cut  squirt  to  cut  the  narrow  lead  strip, 
or  tail,  this  is  torn  by  the  back  tender  or  third  hand  as  the 
paper  passes  from  roll  Mi  to  roll  M2.  He  pushes  his  fingers 
through  the  sheet  about  6  inches  from  the  front  edge  and  gently 
pulls  away  a  narrow  strip,  skillfully  keeping  the  tear  vertical 
till  the  paper  is  safely  on  the  dryers,  when  he  gradually  works 
the  tear  across  the  paper,  finally  breaking  through  the  back 
edge. 

166.  The  third-press  felts  pass  around  the  stretch  rolls  C3,  the 
guide  rolls  G3,  and  the  felt  rolls  Fj,  etc.  On  some  machines, 
there  is  a  very  light  belt  from  the  felt  rolls  to  the  paper  rolls; 
and  the  pulleys  may  be  heavy  enough  to  act  as  flywheels.  It  is 
decidedly  advantageous  to  use  ball  bearings.  An  English  patent 
provides  for  driving  the  bearing,  which,  in  turn,  imparts  motion 
to  the  paper  roll.  When  not  so  provided,  it  is  usually  necessary 
to  start  the  rolls  turning  by  hand. 

Fig.  50  shows  the  characteristic  features  of  a  press  part  of  a 
paper  machine,  including  the  reversal  of  the  paper,  which  is 
generally  done  at  the  last  press,  regardless  of  whether  there  are 
two  presses  or  more  than  two.  The  reader  should  study  this 
drawing  carefully,  making  himself  so  familiar  with  the  run  of  the 
felts  that  he  can  see  them  in  his  mind,  as  it  were;  he  should  make  a 
practice  of  sketching  from  memory  the  run  of  felts  on  paper 
machines;  unless  he  is  perfectly  familiar  with  this  detail,  he 
cannot  expect  to  understand  press-part  problems,  which  are 
frequently  coming  up  for  discussion  and  solution. 

There  is  a  slight  increase  in  surface  speed  at  each  successive 
press,  from  presses  to  drj^ers,  and  from  dryers  to  calenders;  this 
increment  is  called  the  draw,  a  term  also  applied  to  the  unsup- 
ported paper  passing  from  one  part  to  another. 


106 


PAPER-MAKING  MACHINES 
DETAILS  OF  PRESS  PART 


§6 


PRESS  HOUSINGS 

167.  Types  of  Press  Housings. — Fig.  51  shows  typical  sketches 
of  four  different  designs  of  press  hovisings;  designs  (a)  and  (6) 
are  for  use  on  light,  narrow  machines,  while  designs  (c)  and  (d) 


Fig.  51. 

are  for  use  on  heavier,  wider  machines.  These  designs  will  now 
be  considered  in  the  order  named. 

The  housing  (a)  has  a  swinging  arm  B,  pivoted  at  P  on  frame 
F,  which  carries  the  journals  J  of  the  upper  press  roll  K.  The 
lower  press  roll  Ki  is  supported  by  journals  in  separate  bearings 
on  the  press  frame,  as  indicated  at  Ai,  A 2,  A-.^,  Fig.  50.  Arm  B 
is  raised  or  lowered  by  turning  hand  wheel  W,  which  turns  screw 
S  through  the  pivoted  nut  A'^.  The  reader  will  note  that  this  is 
a  lever  of  the  third  class. 

In  the  case  of  the  housing  shown  at  (6),  the  operator  raises  or 
lowers  the  arm  L  carrying  journal  J  of  the  upper  press  roll  iC  by 


§6  THI^]  PRESS  PART  107 

turning  the  hand  wheel  here  indicated  by  the  circle  W.  The 
shaft  of  this  hand  wheel  carries  a  worm  G,  which  meshes  with  the 
worm  gear  N;  the  latter  acts  as  a  stationary  nut,  and  raises  or 
lowers  the  hfting  link  S,  thereby  moving  the  swinging  arm  L 
about  the  pin  P.  F  isa  felt  roll,  and  H  isa  hook  for  attaching  the 
levers  to  put  extra  pressure  on  the  upper  roll.  (See  Wi,  W^,  and 
Ws,  Fig.  50.) 

In  the  case  of  the  housing  shown  at  (c),  the  swinging  arm  L  is 
raised  or  lowered  by  means  of  the  hand  wheel  W;  this  housing  is 
the  reverse  of  that  shown  in  (6).  The  bevel  gear  G  on  the  hand- 
wheel  shaft  meshes  with  a  larger  bevel  gear  N,  which  acts  as  a  nut 
and  screws  the  lifting  screw  S  up  or  down,  thus  raising  or  lowering 
the  upper  press-roll  arms. 

In  the  housing  shown  at  (d),  the  swinging  arm  L  (a  bell  crank) 
carries  the  upper  press  roll  K,  and  is  raised  or  lowered  by  means 
of  a  hand  wheel,  which  is  here  indicated  by  the  dotted  circle 
W.  A  worm  wheel  G  is  keyed  to  the  hand- wheel  shaft  and  meshes 
with  a  worm  gear  N.  The  latter  turns  as  a  stationary  nut  for 
screw  S,  which  causes  screw  S  to  push  against  the  lower  corner  of 
the  bell-crank  lever  L. 


PRESS-ROLL  WEIGHTS  AND   LEVERS 

168.  A  Typical  Arrangement. — Fig.  52  shows  a  typical  arrange- 
ment of  weights  and  levers  for  controlling  the  pressure  of  an 
upper  couch  roll,  or  an  upper  press  roll,  on  the  paper  and  on  the 
lower  roll.  The  hanger  is  made  in  four  parts,  the  top  part  hook- 
ing into  the  swinging  arm  at  H,  Fig.  51(6),  that  carries  the  top  roll; 
in  Fig.  52,  this  part  is  simplj^  an  eye  bolt  B.  The  second  part  is 
the  turn  buckle  T,  which  is  used  to  adjust  the  length  of  the 
hanger.  The  third  part  H  completes  the  turn  buckle.  The 
fourth  part  £'  is  a  long  eye  bolt  that  carries  lever  L,  which  presses 
with  its  short  end  under  the  flange  of  the  press  frame,  as  shown 
in  view  (6) ;  it  is  hung,  and  pulls  down  on  the  center  of  the  hanger 
E  at  P,  holding  hanger  F  on  its  long  end.  Hanger  F  is  a  tee-(T) 
headed  bolt,  the  tee  head  resting  on  the  long  end  of  lever  L. 
The  nut  on  the  bottom  end  of  F  holds  in  place  a  wedge-shaped 
washer  casting  C,  on  which  rests  the  lever  G,  the  hanger  F  passing 
through  the  lever.  The  short  end  of  lever  G  turns  on  pin  M  as  a 
fulcrum,  and  on  the  long  end,  the  necessary  weights  are  placed, 
as  shown  at  W. 


108 


PAPEll-MAKING  MACHINES 


§6 


169.  Pressure  Produced  by  the  Weight.— If  the  weight  W, 
Fig.  52,  be  so  placed  that  the  distance  di  from  the  center  of 
gravity  of  the  weight  to  the  center  of  the  pin  Af  is  8  times  the 
distance  di  between  the  center  of  the  wedge-shaped  casting  C 
and  the  center  of  the  pin  M,  then  the  resultant  pull  downwards 
on  hanger  F  is  8  times  the  weight  W.  If  W  weighs  50  pounds, 
the  downward  pull  (pi)  on  /^  is  8  X  50  =  400  pounds;  this  is 


K 


H 

y 


# 


E 


Kj 


J 

r 

w 

/F^ 

(^ 

W^il^h 

G 

/- 

'" 

""■ 

^ 

m 

t\ 

( 

J 

/ 

V 

Ca)  Cb) 

Fig.  52. 

exerted  on  the  end  of  lever  L,  the  length  of  whose  power  arm  is 
indicated  by  di,  and  the  length  of  whose  weight  arm  is  indicated 
by  di.  Suppose  these  lengths  are  carefully  measured,  and  it  is 
found  that  d^  =3  X  ^4;  then  the  resultant  pull  (7)2)  on  E  is  3 
times  the  pull  on  F,  or  400  X  3  =  1200  pounds,  which  is  exerted 
downwards  on  the  swinging  arm  that  holds  the  upper  roll.  The 
arrangement  is  evidently  a  compound  lever,  in  which  the  power 
arms  are  represented  by  di  and  di,  and  the  weight  arms  by  di  and 
di.  Since  di  -r-  d^  =  8,  and  di  ^  di  =  ^,  the  velocity  ratio  of 
the  combination  (its  mechanical  advantage)  is  8  X  3  =  24. 
Therefore,  the  pull  on  E  is  50  X  24  =  1200  pounds,  the  same 
result  as  before. 


§6  THE  PRESS  PART  109 

In  the  housing  shown  in  Fig.  51(6),  the  ratio  of  the  lengths  of 
power  arm  d^  and  the  weight  (pressure)  arm  d^  is  dr,:  de  =  13:9, 
Therefore,  the  total  theoretical  pressure  exerted  at  the  line  of 
contact  of  rolls  K  and  Ki  by  the  weight  TT  is  50  X  8  X  3  X  V- 
=  1733^  pounds.  The  velocity  ratio  of  the  entire  combina- 
tion is  8  X  3  X  '/  =  34f .  Since  there  is  a  similar  combination 
on  either  end  of  this  roll,  a  pressure  of  at  least  1700  X  2  =  3400 
pounds  will  be  obtained  on  the  nip  between  the  rolls  by  hanging 
a  weight  of  50  pounds  on  the  levers  G,  Fig.  52,  in  the  position 
shown;  and  to  this  must  be  added  the  weight  of  the  top  roll. 
It  is,  however,  the  weight  per  inch  width  of  press  roll  that  counts 
in  pressing  the  paper. 

170.  Press-Roll  Details. — When  a  machine  is  exceptionally 
wide,  the  top  press  roll  is  exceptionally  heavy;  and  it  is  well  to 
remember  that  it  is  not  good  practice  to  subject  the  rubber 
covering  of  the  press  roll  to  a  pressure  of  more  than  50  pounds  per 
lineal  inch  of  face,  more  especially,  if  the  rubber  covering  be 
soft.  This  pressure  is  often  largely  exceeded  to  the  detriment  of 
the  rubber  covering.  The  machine  tender  should  add  only 
weight  enough  to  cause  the  top  and  bottom  rolls  to  meet  at 
every  point  across  the  line  of  contact. 

Rubber  covers  on  lower  press  rolls  were  used  at  first,  instead  of 
wood  and  brass  coverings,  for  two  reasons:  one  reason  was  to 
save  the  felt;  the  other  reason  was  to  obtain  a  compressible  roll, 
to  compensate  for  insufficient  crowning.  The  weights  (W,  Fig. 
52)  are  used  for  obtaining  the  necessary  compression  of  the  roll 
surface,  to  close  all  gaps  between  the  press  rolls.  On  narrow 
machines,  a  softer  rubber  covering  can  be  used  than  on  wide 
machines;  and  the  use  of  levers  and  weights  on  the  press  arms 
is  more  practical  for  the  correction  of  the  small  errors  in  crowning 
that  may  occur  on  machines  up  to,  say,  120-inch  face  of  rolls. 
On  wide  machines,  a  closer  approximation  to  the  correct  crown, 
when  the  bottom  roll  is  first  crowned,  permits  the  use  of  a 
stiff er  rubber  covering  and  a  less  extensive  use  of  levers  and 
weights.  Wide  machines  have  very  heavy  upper  press  rolls; 
indeed,  it  is  hard  to  design  them  so  they  will  not  exceed  50  pounds 
weight  per  inch  of  face. 

Many  machine  tenders,  when  coming  on  their  shift,  alter  the 
position  of  the  weights  on  either  the  couch  roll  or  the  press  roll, 
because  every  man  has  his  own  ideas  regarding  this;  but  the 
pressure  should  always  be  as  light  as  possible  on  a  wide  machine. 


no  PAPER-MAKING  MACHINES  §6 

If  a  press  roll  be  not  ground  accuratelj-,  and  is  larger  in  diameter 
at  one  end  than  at  the  other,  the  paper  will  be  dryer  at  the  larger 
end,  if  the  same  weights  are  used. 

Sometimes  the  steam  in  the  dryers  is  not  properly  controlled, 
and  one  side,  sometimes  the  side  on  the  front  of  the  machine, 
may  be  colder  than  the  other  side;  so  the  machine  tender  tries  to 
correct  the  lack  of  uniformity  of  drying  by  changing  the  weights 
on  the  upper  press  rolls;  but  this  is  poor  practice. 

Press  rolls  should  be  carefully  calipered  with  micrometer 
calipers,  the  diameters  being  taken  for  every  6  inches  of  their 
length.  A  record  should  be  kept  of  these  measurements;  and  if 
the  record  be  plotted,  it  will  show  the  shape  of  the  roll  and  be  a 
useful  guide  to  re-grinding.  The  plot  is  made  by  making  an 
outline  of  the  roll  and  indicating  the  diameters  at  the  proper 
distances  across  it.  The  plot  shows  the  diameter  as  measured  at 
the  distance  indicated  from  the  end  of  the  roll. 


THE  VIBRATING  DOCTOR 

171.  Why  the  Doctor  Is  not  Stationary. — As  previously 
mentioned,  the  doctor  is  used  to  scrape  off  and  collect  the  wet 
broke  from  the  top  press  roll  and  to  collect  particles  adhering  to 
the  roll.  If  the  doctor  were  to  remain  fixed  in  position  while 
scraping,  it  would  soon  reproduce  its  own  inequalities  on  the  shell 
of  the  press  roll,  its  edge  scratching  and  scarring  the  surface.  To 
prevent  this,  doctors  are  provided  with  an  auxiliary  mechanism 
that  causes  them  to  vibrate  to  and  fro,  and  this  motion  results  in 
a  smoothing  action  between  the  edge  of  a  doctor  and  the  surface 
of  the  roll.  The  period  of  alternation  (vibration)  should  not  be 
an  exact  divisor  of  the  time  of  one  revolution  of  the  roll;  for 
instance,  let  a  =  number  of  vibrations  per  minute,  and  h  =  revo- 
lutions per  minute  of  roll,  then  the  quotient  obtained  by  dividing 
6  by  a  must  not  be  an  integer  (whole  number) ;  otherwise,  the 
same  inequalities  will  come  together  at  regular  intervals.  By 
giving  proper  attention  to  this  detail,  the  roll  surface  and  the 
doctor  edge  will  remain  smooth. 

172.  Description  of  Vibrating  Mechanism.- — The  mechanism 
for  vibrating  the  doctor  is  shown  in  Fig.  53.  A  worm  casting  W 
is  fastened  to  the  press-roll  journal  by  set  screws;  it  meshes  with 
the  worm  wheel  IFi,  which  is  keyed  to  shaft  S.  As  the  top 
press  roll  turns,  worm  11^  turns  with  it,  and  this  causes  worm  wheel 


§6 


THE  PRESS  PART 


111 


Wi  and  shaft  S  to  turn  also,  but  very  slowl}-  compared  with  the 
speed  of  the  roll.  One  end  of  lever  L  is  fastened  to  the  top  of 
shaft  S  bj'  a  tap  bolt  Ti,  the  center  line  of  which  is  eccentric  to 
the  center  line  of  the  shaft  S;  hence,  the  center  line  of  Ti  revolves 
around  the  axis  of  the  shaft  when  the  shaft  S  turns,  and  this 
causes  the  end  of  lever  L  to  turn  around  the  same  axis.     This 


Fig.  53. 

movement  compels  the  other  end  of  the  lever,  which  is  fastened 
by  tap  bolt  T2  to  doctor  D,  to  move  to  and  fro  a  short  distance  in 
a  direction  that  is  across  the  machine,  and  thus  gives  the  doctor  a 
vibrating  motion.  The  position  of  the  doctor  blade  with  refer- 
ence to  the  top  of  the  roll  is  adjusted  by  means  of  screw  V;  there 
are  two  such  screws,  one  at  either  end  of  the  doctor.  The 
doctor  blade  may  be  made  of  steel,  brass,  hard  rubber,  or  vulcan- 
ite; the  latter  two  substances  have  less  wearing  action  on  the  roll, 
and  they  do  not  rust  or  corrode. 


112  PAPER-MAKING  MACHINES  §6 

SUCTION  PRESS  ROLLS 

173.  Lining  Up  the  Suction  Rolls. — Mention  may  here  be  made 
of  the  suction  press  rolls,  which  are  now  often  used  on  the  first 
press  and  sometimes  on  the  second  press.  The  mechanical 
operation  of  the  suction  press  roll  is  much  the  same  as  that  of  the 
suction  couch  roll,  and  the  same  degree  of  care  must  be  exercised, 
when  installing  one,  to  get  the  suction  roll  lined  up  with  the  rest 
of  the  machine.  In  this  case,  however,  the  upper  roll  is  not 
eliminated. 

The  position  of  the  suction  box  inside  of  the  suction  roll  requires 
very  careful  adjustment.  On  account  of  varying  conditions,  it 
may  be  necessary  to  try  the  suction  box  in  several  positions 
before  the  correct  one  is  definitely  determined.  Some  experi- 
menting may  also  be  required  in  connection  with  the  kind  of 
felts  used,  it  having  been  found  that  what  works  well  in  one  mill 
is  not  always  best  suited  to  conditions  in  another  mill.  It  is 
recommended  that  the  felts  used  on  a  suction  press  roll  never  be 
turned  over;  hence,  such  felts  need  be  napped  on  one  side  onl}^ 
When  running  on  a  suction  press  roll,  felts  should  last  very  much 
longer  than  when  running  over  the  old-style  press  rolls. 

174.  Construction  and  Operation. — The  top  roll  may  be  of 
wood  or  it  may  be  rubber  covered  or  of  granite,  depending  on  the 
character  of  the  paper  being  made.  When  given  the  proper 
crown,  a  wood  roll  works  very  well  in  most  cases.  The  face  of 
the  suction  press  roll  is  straight,  and  all  crowning  that  is  necessary 
must  be  given  to  the  top  roll,  the  function  of  which  is  to  smooth  the 
surface  of  the  paper.  If  wet  streaks  appear  in  the  sheet  as  it 
leaves  the  suction  press,  it  is  certain  that  the  top  press  roll  is  either 
unevenly  weighted  or  is  incorrectly  crowned.  The  top  roll  should 
not  be  weighted  any  more  than  is  absolutely  necessary,  since  the 
suction  of  the  bottom  roll  does  most  of  the  de-watering.  This 
latter  feature  accounts  for  the  ability  to  make  a  bulkier  sheet  over 
suction  rolls.  As  it  leaves  the  suction  press  roll,  the  sheet  should 
be  carried  up  over  a  draw  roll  of  small  diameter;  if  left  on  the  felt, 
the  sheet  will  have  a  tendency  to  absorb  moisture  from  the  felt. 

175.  As  fast  as  any  water  is  pressed  out  by  the  top  roll,  it  is 
immediately  carried  away  by  the  bottom  suction  roll;  this 
eliminates  the  usual  pond  of  water  that  collects  at  the  nip  of 
plain  press  rolls,  which  is  caused  by  the  up-coming  surface  of  the 
plain  bottom  roll  constantly  carrying  the  pressed-out  water  back 


§6 


THE  PRESS  PART 


113 


"^- 


S 


into  the  nip  of  the  rolls.     This  action  further  eliminates  blowing, 

crushing,     felt    marking,    and    such 

kindred  troubles  as  are  caused  by  the 

objectionable   pond  of  water  that  is 

always  seen  at  the  nip  of  plain  press 

rolls. 

Large  volumes  of  air  are  constanth^ 
being  drawn  through  the  felt  and  into 
the  suction  roll;  this  action  tends  to 
keep  the  felt  open  and  clean,  so  that 
less  frequent  washing  is  required.  On 
machines  making  krafts  and  manilas, 
for  instance,  no  felt  washing  is  done, 
except  at  the  time  of  the  regular 
weekly  shut  down. 

The  suction  press  largely  prevents 
first-press  breaks,  irrespective  of  the 
condition  of  the  stock  and  of  the  speed 
of  the  machine.  The  atmospheric 
pressure  holds  the  sheet  down  on  the 
felt,  while  it  passes  over  the  suction 
area,  with  a  force  sufficient  to  over- 
come its  natural  tendency  to  stick  and 
follow  up  on  the  top  roll. 


FELT  SUCTION  BOXES 

176.  Description  of  Felt  Suction 
Box. — Felt  suction  boxes  are  similar 
in  design  to  the  wire  suction  boxes, 
except  that  no  arrangement  is  made 
for  reducing  the  suction  area  when  a 
box  without  cover  is  used;  that  is,  the 
rubber  piston  and  the  adjustments  for 
it  are  omitted.  The  felt  suction  box 
shown  in  Fig,  54  is  made  from  a  pipe 
P,  on  top  of  which  is  a  trough  A  for 
the  purpose  of  keeping  the  felt  F  from 
actual  contact  with  the  pipe  and 
closing  the  holes  H,  which  are  2 
inches  in  diameter.    As  the  felt  passes 


-i    d 

=^ 


114  PAPER-MAKING  MACHINES  §6 

over  the  trough,  the  suction  tends  to  draw  the  felt  down  into 
the  trough,  up  to  the  holes  H.  Since  the  felt  is  being  stretched 
tight  as  it  moves,  the  force  of  the  suction  simply  draws 
the  felt  down,  as  indicated  bj^  the  dotted  hne  in  the  end  view, 
just  enough  to  make  the  contact  between  the  felt  and  the  edges 
of  the  trough  sufficiently  air-tight  and  water-tight  to  allow  the 
strip  between  the  edges  of  the  trough  to  have  a  part  of  its  con- 
tained water  sucked  out  and  drawn  into  the  pipe  P.  The  suction 
box  is  drained  at  >S.  A  perforated  wood  top  similar  to  the  type 
used  on  the  wire  is  preferred  b}-  many,  who  claim  this  type  is  less 
wearing  on  the  felt. 

177.  Operation. — There  is  no  particular  need  for  altering  the 
width  of  the  suction  area  of  a  felt  suction  box;  because  the  felt  is 
always  wet,  whatever  the  width  of  the  paper  being  made,  and  a 
felt  suction  box  is  used  to  dry  the  felt.  However,  the  limiting  of 
the  length  of  the  active  suction  area  to  the  width  of  the  paper  will 
give  a  better  vacuum. 

Felt  suction  boxes  are  generally  placed  below  the  felts,  just 
before  they  enter  the  nip  of  the  first  and  the  second  presses.  If 
the  felt  be  kept  as  dry  as  possible,  the  presses  are  helped  in  their 
work  of  pressing  the  water  out  of  the  paper  into  the  felt  that 
carries  the  paper  between  the  presses.  The  edges  and  tops  of 
felt  suction  boxes  must  be  kept  as  smooth  as  possible,  to  guard 
against  damaging  the  felt  as  it  passes  over  the  box  and  is  dragged 
into  it  by  the  suction. 

Felt  suction  boxes  are  built  in  many  ways;  a  pipe  suction  box  is 
here  described,  not  because  it  is  superior  to  other  designs,  but 
because  it  illustrates  better  the  principal  features  of  a  good  suction 
box.  The  use  of  a  perforated  cover,  similar  to  that  on  a  wire 
suction  box,  is  allowable,  provided  there  is  a  smooth  surface 
and  no  sharp  edges  that  will  wear  the  nap  off  the  felt.  Such  a 
cover  is  made  of  wood,  with  diagonal  slots,  which  overlap  enough 
to  provide  a  drj-ing  action  over  the  whole  width  of  the  felt. 

It  must  not  be  forgotten  that  the  suction  box  acts  also  like  a 
brake  on  the  felt,  and  that  a  heavy  suction  must  necessarily 
shorten  the  life  of  the  felt. 

PRESS-FELT  STRETCHERS 

178.  A  Typical  Design. — In  Fig.  55  is  shown  a  typical  design 
of  a  hand-operated  stretcher  for  a  press  felt.  The  press-felt 
roll  R,  which  carries  the  half  lap  of  felt,  is  supported  by  journals 


§6 


THE  PRESS  PART 


115 


that  turn  in  the  brackets  F;  and  a  screw  thread  T,  Fig.  56,  in 
each  portion  of  the  brackets  fits  inside  the  brass  pipes  P  and  Pi. 


nf^o. 

\ 

n  1 

■/ir": 1  if 

[ 

s 

<ff 

] 

c 


s^. 


Hi 


T-T, 

Brass  Pipe 

ScrewThreadI 


Fig    55. 

In  both  pipes,  there  is  a  slot  throughout  nearly  its  whole  length, 

to  allow  the  brackets  to  slide  along  the  outside  of  the  pipes  and 

also    to    project   inside,   so   as   to 

engage  the  threaded  shaft  T\  that 

runs  inside  of  the  pipe.     Fig.  56, 

which  is  an  enlarged  sectional  view, 

shows  this  detail  more  clearly.   The 

screw  T\  can  turn,  but  cannot  move 

otherwise.     The  screws  have  bevel 

(miter)  gears  G  at  one  end,  the  gears 

meshing  with  them  being  on  shaft  <S. 

By  turning  hand  wheel  IF,  shaft  S 

and  the  miter  gears  revolve;  this 

causes  the  screws  in  the  pipes  on 

either  side  of  the  machine  to  turn 

equally  until  the  brackets  carrying 

the    felt    roll    are    in   the    correct 

position  to  keep  the  felt  in  the  state  of  tension  required.    Fig.  55 

shows  the  stretcher  furnished  with  a  bracket  B  on  one  end  of 


(aj 


Section  on  X-X  Fig.  oj  (Enlargerl) 
Fig.  56. 


116 


PAPER-MAKING  MACHINES 


§6 


? 


v.rm 


i.^W 


each  pipe,  to  bolt  to  the  side  of  a  housing 
or  upright  casting,  and  a  bracket  C  on  the 
other  end,  to  bolt  to  the  press  frame. 

179.  Velocity  Ratio  of  Stretcher.— This 
stretcher  gives  the  machine  tender  a 
velocity  ratio  of  several  hundred  to  one, 
according  to  the  pitch  of  the  screw  and  the 
other  dimensions.  Fortunately,  the  efl&- 
ciency  of  such  a  piece  of  machinery  is  not 
over  25%;  otherwise  the  felts  would  be 
overstretched,  more  than  they  are  now  on 
many  a  machine. 

It  is  customary  to  have  a  cam  arrange- 
ment that  will  throw  out  the  gears  on  the 
front  side,  so  the  back  end  of  the  stretch 
roll  can  be  operated  forward  or  backward 
of  the  position  of  the  front  end,  in  order 
to  make  up  for  inequalities  in  the  length 
of  the  felt. 

FELT  WHIPPERS  AND  SHOWERS 

180.  Felt  Whippers.— The  felt  whipper, 
see  Fig.  57,  is  designed  with  2,  3,  or  4 
blades  A,  which  are  bolted  to  spiders  B. 
The  blades  are  made  almost  always  of 
wood,  and  the  outer  extremities  are  rounded 
to  an  arc  of  a  circle,  as  shown.  Brass  pipes 
may  be  used  instead  of  blades.  The  spiders 
B  are  mounted  on  a  shaft  S,  which  carries 
the  driving  pulley  P.  The  whippers  are 
placed  on  the  outside  of  the  felt;  they 
revolve  at  about  125  r.p.m.,  and  in  a  direc- 
tion such  that  the  edge  of  the  blades  will 
not  knock  the  nap  off  the  felt.  The  rapid 
motion  of  the  whipper  causes  the  felt  to 
vibrate  forcibly  against  its  blades,  which 
beat  out  the  dirt  from  the  felt.  A  strong 
shower  (Ji  and  J2,  Fig.  50)  is  directed 
against  the  inside  of  the  felt,  to  wash  out 
the  loosened  dirt.  The  shower  is  generally 
placed  after  the  whipper  (in  the  direction 


§6 


THE  PRESS  PART 


117 


in  which  the  felt  is  traveUng),  though  some  designers  prefer  to 
place  it  before  the  whipper,  as  shown  in  Fig.  50.  The  pulley  P 
is  belt  driven  from  the  nearest  conv^enient  driving  shaft  of  the 
machine.  Care  should  be  taken  so  to  adjust  the  position  of  the 
whipper  that  the  blades  will  not  scrub  against  the  felt,  thus 
wearing  out  the  felt;  it  should  beat  the  felt  with  quick,  sharp 
blows,  which  do  not  tend  to  scrape  off  the  nap.  P'elt  whippers 
are  almost  always  omitted  on  fast  machines. 

181.  Showers. — There  are  several  patented  attachments  for 
washing  felts  without  stopping  the  machine;  for  the  most  part, 
these  consist  of  a  shower  to  distribute  warm  water,  soap,  or  a 
chemical  solution,  and  a  suction  box  to  draw  out  the  dirty  water 
and  loosened  dirt.  On  some  machines,  a  pair  of  squeeze  rolls  are 
used  to  remove  the  water  used  for  washing  the  felt. 

Some  experiments  have  been  made  in  connection  with  the  use 
of  a  steam  jet  instead  of  a  shower;  but  the  higher  temperature  is 
apt  to  shorten  the  life  of  the  felt. 


GUIDE  ROLLS  AND  PAPER  ROLLS 

182.  Auto-Swing  Guide  Rolls. — Fig.  58  shows  the  guide  roll 
G\,  Fig.  50,  in  greater  detail.     The  bearing  of  one  journal  of  the 


SMng  or 
Strip  oFFelf 


Fig.  58. 


guide  roll  R  is  hung  at  P  from  a  pivot  on  the  tending  side  of  the 
machine.  The  bearing  of  the  other  journal  is  carried  in  a 
bracket  B,  which  is  moved  by  an  adjustable  hand  screw  S. 
When  the  hand  wheel  W  on  the  end  of  this  screw  is  turned,  the 
bracket  carrying  the  guide  roll  is  caused  to  move  by  means  of 
the  screw  thread  that  is  tapped  in  the  bracket,  and  in  which  the 
band  screw  turns.     The  position  of  the  roll  is  so  adjusted  by  this 


118  PAPER-MAKING  MACHINES  §6 

means  that  the  felt  has  a  slight  tendency  to  come  to  the  front 
(tending)  side  of  the  machine. 

The  front  journal,  whose  bearing  is  in  the  swinging  arm  A,  is 
connected  by  a  string  or  strip  of  felt  to  a  cylindrical  wooden  block 
that  fits  loosely  on  the  end  of  an  adjacent  felt  roll  (as  F5,  Fa,  Fig. 
50).  When  the  felt  travels  to  the  front  side  of  the  machine,  it 
climbs  onto  this  wooden  block  and  turns  it;  this  causes  the 
string  to  wind  up  on  the  block  and  pulls  the  guide  roll  toward 
the  block,  thus  correcting  the  travel  of  the  felt.  The  principle 
is  the  same  as  that  explained  in  connection  with  the  wire  guide 
roll.  Fig.  58  shows  the  arrangement  in  perspective.  It  is 
customary  so  to  hang  the  front  end  of  the  guide  roll  that  the  felt 
will  be  guided  forwards  again  when  the  felt  has  left  the  block 
after  the  travel  has  been  corrected.  When  the  felt  has  left  the 
block,  a  counterweight  draws  the  string  back  to  its  former 
position. 

183.  Paper  Rolls. — Since  the  paper  is  weak  when  wet,  it  is 
important  that  the  rolls  over  which  the  paper  travels  shall  turn 
very  easily;  for  this  purpose,  the  bearings  must  be  well  lubri- 
cated. Ball  bearings  are  a  distinct  advantage  here.  An  English 
invention  provides  for  driving  the  bearing,  the  friction  driving  the 
roll,  when  idle,  a  little  faster  than  the  paper  speed. 


MANAGEMENT  AND  CARE  OF  PRESS  PART 


CARE  AND  TREATMENT  OF  FELTS 

184.  Taking  Off  the  Old  Felt— The  method  of  putting  on  a 
new  felt  will  now  be  described.  The  old  felt  is  cut  across  the 
machine  and  rolled  up  by  hand,  the  press  part  being  run  slowly. 
If  the  old  felt  is  to  be  used  again,  as  is  sometimes  the  case  with 
a  wet  or  first-press  felt  that  is  considered  good  enough  to  use 
as  a  second-press  felt,  or  if  it  is  to  be  washed,  the  old  felt  is 
taken  out  as  follows:  Clean  the  ends  of  press  rolls,  bearings,  etc., 
thoroughly;  slack  up  on  stretch  roll;  raise  upper  press  roll  by 
means  of  the  housing  (lever),  and  pull  out  the  old  felt  from 
between  the  rolls;  lay  the  felt  over  the  upper-roll  bearing;  lower 
front  end  of  upper  roll,  and  slip  5'oke  or  loop  over  the  journals 
of  the  upper  and  lower  rolls;  raise  again  on  the  lever,  which  will 
lift  lower  journal  from  its  bearing  and  permit  the  removal  of  the 


§6 


THE  PRESS  PART 


119 


Top  Press 
She/  Link 


'Boffom  PreS'S. 


pedestal;  take  out  lower  side  of  old  felt;  the  pedestal  is  now 
replaced  and  the  rolls  lowered.  The  felt  is  now  outside  the  press 
rolls,  and  it  may  be  removed  by  lifting  the  ends  of  the  felt  rolls 
and  slipping  the  felt  over  them. 

185.  Putting  On  a  New  Felt. — All  grease  and  dirt  must  now  be 
thoroughly  removed  from  the  frame  and  from  the  front  ends  of 
the  rolls,  and  from  any  place  the  felt  may  touch;  the  trough  under 
the  roll  is  removed.  The  new  felt  should  be  laid  out  full  length, 
preferably  on  the  foot  bridge  across  the  machine  or  on  the  clean 
tending  floor,  with  the  nap  of  the  felt  lying  down  with  the  run 
of  the  paper.  The  felt  is  not  laid 
out  full  width,  but  is  doubled  on 
itself  in  folds  until  its  width  is 
reduced  as  much  as  possible.  It 
is  a  good  plan  to  lay  out  and 
arrange  the  felt  on  the  clean  floor 
of  the  felt  room.  Don't  walk  on 
it.  The  top  press  roll  is  then 
raised  by  the  housing,  and  the 
felt  is  placed  between  the  journals 
of  the  two  press  rolls,  with  the 
nap  so  it  will  lie  down  when  the 
felt  is  running,  the  cap  on  the 
lower  roll  being  removed,  and  the 
journal  and  bearing  wiped  clean, 
until  the  steel  hnk  is  in  place  over  the  two  press  journals.  The 
hnk  is  inside  of  the  felt,  as  shown  in  Fig.  59.  When  the  link  is  in 
position,  the  top  press  is  again  raised  by  means  of  the  mechanism 
already  described;  this  raises  the  lower  roll  also.  The  bracket 
and  bearings  under  the  lower  roll  are  then  removed,  and  the 
frame  and  journal  are  wiped  clean. 

The  felt  is  then  passed  over  the  end  of  the  lower  roll,  and  the 
bearing  is  carefully  replaced.  The  rolls  are  lowered,  the  journal 
of  the  link  is  removed,  and  the  top  roll  is  raised  until  the  felt 
can  be  spread  out  between  the  rolls.  The  felt  is  then  pulled  out 
lengthwise,  so  that  it  extends,  while  still  as  narrow  in  width  as 
possible,  along  the  inside  of  the  machine  in  the  path  in  which  it  is 
to  travel.  When  a  machine  tender  reaches  a  felt  roll,  as  he  is 
pulling  out  the  felt  along  the  machine,  he  lifts  the  roll  out  of  its 
bearing  and  puts  the  felt  over  the  end  of  the  roll;  and  this  is 
done  with  all  the  felt  rolls  that  run  inside  the  felt,  if  the  felt  is 


The  top  press  is  then  lowered 


120  PAPER-MAKING  MACHINES  §6 

long  enough.     If  necessary,  the  stretch  (or  hitch)  roll  is  taken 
out  and  put  in  last. 

The  felt  is  now  in  its  proper  place,  but  it  is  all  rumpled  up. 
It  can  be  edged  across  the  machine  gradually  by  running  the 
press  part  slowly,  with  the  top  roll  down  just  enough  to  catch 
the  felt  and  pulling  the  felt  across,  using  the  guide  roll  to  help  in 
doing  this.  While  it  may  take  longer,  the  felt  will  last  longer 
than  when  it  is  pulled  and  hauled  across  the  width  of  the  machine 
by  main  force.  Give  the  felt  time  to  adjust  itself,  without 
trying  to  increase  production  by  gaining  a  few  minutes  at  the 
expense  of  the  felt. 

186.  Wetting  the  Felt. — When  the  felt  is  across  the  machine 
and  the  stretch  roll  is  in  place  at  its  shortest  stretch,  the  upper 
roll  is  lowered  and  the  felt  is  wetted.  The  wetting  should  not 
be  done  with  a  hose,  because  it  is  very  easy  to  spoil  a  new  felt 
by  getting  too  much  water  in  one  place;  a  buckle  caused  by  such 
action  cannot  be  removed.  A  shower  pipe  across  the  machine 
should  be  used  to  wet  the  new  felt  gradually,  care  being  taken 
that  the  felt  is  not  moving  until  a  steady,  even  stream  of  water  is 
flowing  over  one  roll  across  the  full  width  of  the  felt. 

The  foregoing  description  of  the  method  of  replacing  a  felt  is 
applicable  to  all  felts  on  press  parts.  On  a  cylinder  or  Harper 
machine,  there  is  more  than  one  pair  of  presses,  but  the  method  of 
placing  the  felt  over  the  press  rolls  is  practically  the  same  in  all  cases. 

187.  Felt  Marks. — Felt  marks  are  the  principal  cause  of 
many  troubles  that  develop  at  the  press  part  of  the  paper 
machine.  The  phrase  "felt  mark  on  the  paper"  is  usually  a 
misnomer;  it  is  the  impression  made  by  the  threads  of  the  felt 
only  in  the  case  of  old  or  too  coarse  felts,  but  is  generally  applied 
to  the  defects  in  the  paper  caused  by  the  gradual  filling  in  of  spots 
in  the  felts  meshes,  which  make  the  felt  harder;  the  final  result 
is  the  accumulation  of  stock  and  filler,  which  destroys  the  ability 
of  the  felt  to  press  water  from  the  paper,  and  a  blotch  is  formed. 
The  water  can  escape  when  pressed  out  from  the  paper  only  by 
passing  through  the  felt  meshes  at  the  side  of  these  spots.  The 
only  remedy  for  this  trouble  is  to  clean  the  felt.  When  the 
felt  is  new,  and  if  the  lower  rubber-covered  roll  be  not  too  hard, 
a  new  felt  should  run  satisfactorily  for  48  hours  without  washing; 
but,  as  the  felt  ages,  the  time  between  washings  is  reduced,  and 
felt^  finally  have  to  be  cleaned  every  24  hours. 


§6  THE  PRESS  PART  121 

188.  Washing  the  Felt. — The  felts  are  washed  on  the  machine 
as  follows: 

Remove  all  weights  and  levers;  then  slack  the  felt  by  moving 
the  stretch  roll  back  as  far  as  it  will  go.  Turn  a  strong  stream  of 
clean  water  on  the  felt,  and  push  the  felt  on  itself,  toward  the 
center,  until  there  is  a  clear  space,  about  2  feet  wide,  from  both 
ends  of  the  rolls.  Allow  the  felt  to  run  in  the  water  this  way 
until  clean,  or  for  about  45  minutes  in  the  worst  cases.  When 
it  is  observed  that  the  water  that  is  being  washed  through  the 
felt  is  coming  away  clear  and  clean,  it  indicates  that  the  felt  has 
been  washed  sufficiently.  It  may  then  be  pulled  flat  by  gradually 
drawing  the  edges  to  the  front  and  back  sides  of  the  machine; 
keep  the  hands  away  from  rolls,  avoid  danger.  Before  pulling 
out  the  felt,  clear  it  of  wrinkles;  if  it  be  a  double-napped  felt, 
turn  it  over,  so  the  outside  will  be  on  the  inside;  this  will  insure 
that  the  felt  wear  uniformly  on  both  sides;  it  will  also  give  a 
longer  running  time  between  wash-ups,  because  the  newly- 
washed,  dirty  side  of  the  felt  is  now  on  the  inside,  and  the  water 
pressed  from  the  paper  that  leaves  the  felt  from  this  side  will  carry 
off  all  the  fine  particles  in  the  felt  that  may  have  remained  after  the 
felt  washing.  A  weak  solution  of  soap  or  soda  ash  is  sometimes 
poured  on  the  felt  to  assist  in  the  cleaning.     (See  also  Art.  181.) 

189.  Care  and  Life  of  Felts. — A  felt  that  is  properly  cared  for 
should  give  3  or  4  weeks  of  service  on  a  fast  news  machine,  which 
is  very  hard  on  felts,  because  of  its  high  speed  and  the  quality 
of  the  stock.  On  the  slower  running  book  machines,  there  is  no 
reason  why  a  felt  should  not  last  much  longer.  The  elimination 
of  rolls  running  on  the  outside  of  the  felt  lengthens  the  life  of  the 
felt.  Such  rolls  gather  particles  of^fiber,  forming  lumps  that 
dirty  the  felt. 

With  good,  smooth,  brass-covered  felt  rolls  of  proper  stiffness, 
with  the  upper  press  roll  kept  in  good,  smooth  order,  with  the 
rubber-covered  roll  not  too  hard,  and  with  the  right  amount  of 
crown,  the  machine  tender  who  exercises  common  sense  regarding 
the  amount  of  tension  he  puts  on  the  felt  at  the  stretch  roll,  may 
solve  all  the  mysteries  of  how  to  get  the  longest  wear,  the  longest 
run  between  wash-ups,  together  with  a  minimum  of  breaks  and 
felt  marks. 

190.  General  Rules  for  Washing  Felts. — At  this  point,  it  is 
advisable  to  give  some  instructions  regarding  the  proper  washing 


122  PAPER-MAKING  MACHINES  §6 

of  felts.  Cases  are  known  where  a  felt  has  been  run  in  the  washer 
for  nearly  a  full  day;  such  treatment,  of  course,  practically  ruins 
the  felt.  The  following  are  general  instructions  for  the  proper 
washing  of  felts  when  the  washing  is  done  off  the  machine: 

The  temperature  of  the  water  should  not  exceed  120°F.; 
that  is,  it  should  not  be  hotter  than  one  can  comfortably  bear 
when  placing  his  hand  in  it,  since  a  higher  temperature  injures 
the  wool  fibers. 

The  quantity  of  soap  to  be  used  varies  with  the  amount  of  dirt 
to  be  removed  from  the  felt,  and  with  the  amount  of  size  that 
has  been  used  on  the  paper;  however,  enough  soap  should  be 
used  to  give  a  good  lather. 

Use  a  good  neutral  soap  that  rinses  out  readily,  and  do  not  use 
strong  alkalis,  because  alkalis  containing  caustic  will  dissolve 
wool  fibers.  There  are  brands  of  soap  that  have  been  specially 
prepared  for  this  purpose,  and  one  of  these  should  be  employed; 
the  ordinary  soap  used  about  the  mill  is  not  satisfactory  for 
felt-washing  purposes. 

If  felts  are  washed  in  warm  water,  it  is  much  better  to  reduce 
the  temperature  of  the  water  gradually,  while  the  felts  are  being 
rinsed,  until  the  natural  temperature  of  the  water  is  reached;  sud- 
den changes  in  temperature  change  the  original  texture  of  the  felt. 

The  felt  should  not  be  run  in  soap  more  than  20  minutes,  and  it 
should  be  rinsed  only  long  enough  to  wash  out  the  soap,  say 
another  20  minutes.  If  a  new  soap  is  bought,  try  it  out  on  a  test 
strip  of  felt.     Never  use  free  acid  on  a  felt. 

191.  Preservation  of  Felts  and  Jackets. — During  the  Great 
War,  the  United  States  Government  studied  the  question  of 
conservation  of  essential  industrial  materials.  The  following 
recommendations  made  with  regard  to  felts  are  worthy  of  careful 
study : 

Watch  the  stock  carefully,  and  keep  it  in  a  cool,  absolutely  dry 
place — moisture  causes  mildew  and  destruction  of  wool  fibers. 
Felts  and  jackets  should,  if  possible,  be  kept  in  their  original 
papers,  tied  tightly;  and  see  that  there  are  no  holes  in  the  papers. 
Keep  the  felts  clean;  dirt  injures  them  and  attracts  moths. 
Keep  the  whole  felt  room  clean  and  in  good  order. 

Use  moth  preventives  freely  and  frequently;  strong  tar  paper 
is  good  for  this  purpose,  and  the  shelves  should  be  covered  with 
it.  Flake  naphthalene  is  the  best  preventive,  but  it  evaporates 
and  must  be  renewed.     Sprinkle  the  felts  thoroughly  with  the 


§6  THE  PRESS  PART  123 

naphthalene  and  scatter  it  around  the  felt  room.  Examine 
the  stock  at  least  once  a  month  for  traces  of  moths  or  for  other 
injury.     Use  the  oldest  felts  first. 

Handle  the  felts  with  care  when  taking  them  to  the  machine. 
Felts  are  bulky  and  heavy,  and  they  may  be  torn  by  catching 
on  a  nail  or  anything  sharp;  put  them  down  only  in  clean  places. 
Clean  all  journals  and  bearings  before  putting  on  felts,  to  keep 
the  felts  free  from  grease. 

Above  ever3^thing  else,  the  life  of  a  felt  depends  on  the  con- 
dition of  the  machine.  See  that  all  press  rolls  are  turned  with 
the  proper  crown  to  assure  the  very  best  running  conditions; 
press  or  felt  rolls  that  are  in  bad  condition,  rough  suction-box 
covers  and  whippers,  and  badly  made  spread  rolls,  often  reduce 
length  of  service  50%,  or  even  75%. 

See  that  every  roll  turns  freely;  cylinder  bearings  should  be 
carefully  w^atched.  All  felts  are  subjected  to  great  strains 
lengthwise,  cylinder  felts  especially.  Don't  stretch  the  felts  too 
tight.  A  large  percentage  of  felts  are  ruined  by  running  under 
unnecessary  strain. 

Felts  on  idle  machines  deteriorate  almost  as  fast  as  when 
running.  When  shutting  down,  raise  the  top  press  roll;  see  that 
the  felt  does  not  come  into  contact  with  iron,  as  rust  quickly  fills 
the  pores;  see  that  the  air  can  reach  it  at  every  point,  so  it  can  dry 
quickly  and  thus  prevent  mildewing. 

Use  care  in  handling  jackets;  they  are  tough  and  strong,  but 
that  is  no  reason  for  rough  treatment.  Be  careful  in  stretching, 
shrinking,  and  tying  down  (lacing);  watch  the  condition  of  the 
guard  boards;  above  all,  don't  set  guard  boards  down  tighter 
than  is  necessary.  Don't  take  off  felts  before  they  are  worn  out; 
get  all  possible  wear  out  of  them,  even  at  some  risk  of  a  shut- 
down during  the  week.  Superintendents  and  foremen  should 
examine  felts  on  machines  before  allowing  them  to  be  taken  off 
and  new  ones  given  out.  Don't  make  blankets  from  felts  that 
can  be  run  longer;  by  observing  this  one  precaution  alone,  some 
mills  have  increased  the  life  of  their  felts  by  weeks. 

Carefully  wash  and  dry  all  used  felts,  and  keep  them  as  clean 
as  possible;  their  value  depends  on  their  condition.  Don't 
destroy  even  small  pieces  of  worn-out  felts;  every  pound  can  be 
used  for  some  purpose. 

For  reasons  of  economy  and  good  business  management, 
superintendents,    foremen,    and   machine   tenders   will   observe 


124 


PAPER-MAKING  MACHINES 


§6 


all  the  foregoing  precautions  and  many  more  that  will  occur  to 
them  in  practice.  In  the  long  run,  greater  production  will  be 
obtained  by  not  being  careless  about  the  condition  of  machines 
or  in  the  use  of  felts  and  jackets.  Take  time  to  put  everything 
in  first-class  condition;  the  time  thus  spent  will  soon  be  made  up. 

192.  Tension  of  Felts. — While  it  is  very  important  to  consider 
the  tension  of  the  felt,  it  is  equally  important  that  the  seam  be 
kept  straight  across  the  felt.  The  seam  will  run  ahead  on  the 
ends  or  at  the  center,  according  to  the  condition  of  the  rolls  and 


Square  Openings 
in  Mesh 


Dicumond  Shape 
Openings  in  Mesh 


Fig.  60. 


the  amount  of  crown  used.  When  the  crown  is  excessive,  the 
seam  will  run  ahead  at  the  center.  When  the  felt  is  unequally 
stressed  in  this  manner,  the  meshes  are  partially  closed,  due  to 
the  diamond  shape  that  they  are  thereby  forced  to  assume; 
this  effect  is  illustrated  in  Fig.  60.  The  left-hand  part  of  the 
figure  shows  the  meshes  (greatly  exaggerated)  when  the  felt  is 
running  properly,  while  right-hand  part  shows  the  meshes 
when  distorted  by  excessive  crowning,  or  by  having  one  side 
run  ahead  of  the  other. 

When  first  put  on,  a  felt  can  run  under  much  less  tension  than 
later,  and  distortion  of  the  weave  has  less  effect,  because  the  felt 
has  enough  nap  to  offset  the  extra  pressure  of  the  rolls.  Further, 
under  these  conditions,  the  tension  is  not  severe  on  the  felt,  and 
it  would  not  then  be  absolutely  necessary  to  correct  for  a  crooked 
seam;  in  fact,  the  remedy  might  be  worse  than  the  disease,  the  felt 
being  caused  to  widen  excessively  and  to  run  against  th«  frames. 


§6 


THE  PRESS  PART 


125 


193.  Influence  of  Tension  on  "Width  of  Felts. — The  extra 
width  on  new  felts  must  not  be  trimmed  off  when  they  are  new; 
it  will  be  needed  later,  when  the  felts  become  thin  with  wear. 
They  should  be  ordered  of  correct  width.  When  it  has  become 
worn,  it  is  obligatory  to  increase  the  tension  on  a  felt,  in  order 
to  open  the  meshes  and  thus  more  readily  release  the  water. 
The  width  of  a  felt  is  controlled  to  a  certain  extent  by  its  tension : 
when  the  tension  is  great,  the  felt  naturally  narrows,  and  it 
spreads  when  the  tension  is  relieved. 

194.  Widening  Felts.— When  a  felt  has  been  narrowed  by  being 
stretched  under  the  tension,  it  can  be  widened  again  by  slacking 
the  stretch  roll  and  making  one  of  the  inside  rolls  (around  which 


Fig.  61. 


the  felt  wraps  more  than  a  quarter  of  a  circle)  into  a  worm. 
This  latter  operation  is  effected  as  shown  in  Fig.  61,  by  tacking  a 
strip  of  felt  to  a  wooden  roll,  or  by  fastening  a  brass  strip  to  the 
roll  either  by  means  of  countersunk  screws  or  by  solderng  it  to 
a  brass  roll.  Examination  of  Fig.  61  shows  that  the  worm  is 
double  threaded  and  that  it  has  right-  and  left-hand  threads, 
the  part  to  the  right  of  A  being  left-handed  and  the  part  to  the 
left  of  A  being  right-handed.  As  the  felt  moves  in  the  direction 
of  the  arrow,  the  friction  between  it  and  the  roll  causes  the  roll  to 
turn  also,  and  the  threads  tend  to  push  the  fibers  away  from  the 
center  A,  which  widens  the  felt. 

A  simple  felt  spreader  may  be  constructed  of  two  light  wood 
rolls,  which  are  a  little  more  than  one-half  the  length  of  the  felt 
rolls;  these  are  supported  under  the  felt,  with  their  axes  making 
a  large  angle  with  each  other  (say  160°),  like  a  shallow  V,  the 
apex  of  which  points  to  and  meets  the  center  line  of  the 
oncoming  felt.  These  rolls,  of  course,  are  dropped  or  otherwise 
taken  out  of  contact  with  the  felt,  when  it  has  been  widened 
enough. 

195.  Guiding  the  Felt. — To  guide  a  felt,  the  end  of  the  guide 
roll  must  be  moved  in  the  direction  in  which  the  felt  is  running, 
if  it  be  desired  to  make  it  travel  away  from  that  end;  but  if  the 


126  PAPER-MAKING  MACHINES  §6 

end  of  the  roll  be  moved  against  the  run  of  the  felt,  the  felt  will 
travel  toward  the  end  that  was  moved. 

If  the  seam,  or  blue  line,  of  a  felt  be  not  parallel  with  the  axis 
of  a  felt  roll,  i.e.,  if  one  end  be  ahead  of  the  other,  the  end  ahead 
can  be  brought  back  by  increasing  the  stretch  on  whichever  end 
of  the  hne  is  ahead.  The  felt  should  be  watched  carefully  when- 
ever a  roll  is  shifted,  to  see  that  its  position  is  not  altered.  In 
cases  where  both  ends  of  the  seam  are  even  (parallel  with  the  axis 
of  a  felt  roll)  and  the  center  is  drawn  back,  add  extra  worming 
in  the  center  of  the  roll,  or  at  any  place  where  the  felt  lags  back. 
Another  remedy  is  to  wind  cotton  twine  (or  a  strip  of  paper 
having  a  little  paste  on  the  ends)  around  the  roll,  in  line  with  the 
lag  places ;  but  care  must  be  taken  not  to  wind  too  much  on  the  roll, 
since  it  is  much  easier  to  add  a  little  more  than  it  is  to  take  some 
off.  This  winding  is  removed,  of  course,  when  the  fault  has 
been  corrected. 

196.  Wrinkles  and  Slack  Places. — In  cases  where  a  straight 
wrinkle  or  lap  appears  in  a  new  felt,  and  this  often  happens  on 
wide  machines  (where  the  rolls  are  inclined  to  spring),  run  the 
felt  slack  and  keep  the  wrinkle  from  running  through  the  press 
by  constantly  pulling  on  the  felt.  But  take  care  not  to  get 
caught  in  the  rolls!  Slack  up  the  tail  and  tighten  up  the  head 
of  the  wrinkle,  by  moving  the  guide  roll  or  stretch  roll.  Hot 
sizing  poured  on  the  wrinkle  will  make  it  disappear  almost 
instantly,  if  the  sizing  be  not  allowed  to  go  through  the  press 
again. 

Another  trouble  is  the  result  of  slack  places  and  thin  streaks  or 
spots,  which  are  due  to  excessive  wear  at  certain  points;  these 
are  frequently  caused  by  accumulations  of  paper  stock  on  a  felt 
roll,  which  stretch  the  felt  in  spots  the  length  of  the  felt,  and  the 
felt  whipper  wears  these  places  thin. 

197.  Analogy  between  Felts  and  Belts. — It  is  readily  perceived 
that  the  felt  acts  like  a  belt,  and  it  drives  many  rolls  that  would 
be  undriven  otherwise;  these  rolls  all  act  as  brakes,  and  to  their 
action  must  be  added  the  braking  action  of  suction  boxes.  It 
is  also  evident  that  the  place  of  greatest  stress  and  strain  is  close 
to  the  driver,  where  the  sum  of  all  the  hold-backs  is  concentrated. 
This  naturally  brings  up  for  consideration  the  matter  of  type 
of  bearings  and  the  kind  of  lubrication  used  on  journals  of  main 
press  rolls  and  of  the  felt  rolls  driven  by  the  felt. 


§6  THE  PRESS  PART  127 

198.  Lubricating  and  Cooling  Journals. — The  journals  of  press 
and  couch  rolls  (unless  ball  bearing)  are  water  cooled.  The  cast- 
ings that  hold  the  bearing  metal  are  hollow,  and  cold  water  is 
circulated  through  them. 

Many  methods  of  lubricating  paper-machine  bearings  are  in 
use,  ranging  from  the  open-top  bearing,  with  a  piece  of  ham  fat 
resting  on  the  revolving  journal,  to  the  more  pretentious  bearings, 
which  have  a  continuous  supply  of  oil  from  a  pump  that  may  get 
out  of  order  or  from  a  reservoir  that  needs  filling.  Capillary  bear- 
ings, which  depend  on  a  lamp  wick  to  draw  oil  from  a  reservoir 
and  w^ipe  it  on  the  journal,  are  also  used  with  good  results. 

Paper-machine  journals  run  at  comparatively  slow  speeds; 
they  should  be  amply  large  for  the  weights  they  support,  and 
should  have  a  cover  over  them,  to  keep  out  dirt  and  water  and 
to  keep  in  the  oil  or  grease.  A  good  millwright  can  often  cure  a 
bearing  that  gives  trouble  by  cutting  two  helical  grooves,  say  ^V 
inch  deep,  on  the  journal,  so  as  to  compel  the  oil  or  grease  to  run 
around  the  journals  until  it  reaches  the  place  where  the  weight  is 
carried.  If  the  millwright  is  sufficiently  experienced,  he  can  tell 
where  these  grooves  ought  to  be  by  examining  the  journals  after 
they  have  begun  to  give  trouble.  Felt-roll  bearings  should 
have  self-alining  bronze  bushings  to  line  up  with  journals  which 
are  frequently  bent. 

199.  While  on  the  subject  of  bearings,  it  may  be  remarked 
that  unless  the  paper  machine  is  kept  running  all  the  time,  and  is 
making  paper  all  the  time,  it  is  not  making  money.  The  cost  of 
power  to  run  it  is  but  a  drop  in  the  bucket  w'hen  compared  with 
the  value  of  the  production  lost  through  the  shut-down  of  the 
machine  for  an  hour  or  so  a  day;  therefore,  keep  the  bearings 
cool.     A  water-cooled  bearing  is  simple  and  practicable. 

200.  Length  of  Felts  and  Number  of  Rolls. — Many  mill  men 
think  a  long  felt  is  better  than  a  short  one;  but,  in  most  cases, 
this  is  far  from  being  true.  If  additional  rolls  accompany  the 
longer  felt,  there  is  no  gain.  For  instance,  a  45-foot  felt  running 
around  9  rolls  is  no  better  than  a  35-foot  felt  running  around  7 
rolls;  in  fact,  it  is  much  worse,  on  account  of  the  extra  hold 
back  of  the  two  additional  rolls,  which  evidently  increases  the 
total  stress  very  near  the  driver.  The  life  of  a  felt  is  materially 
increased  by  reducing  the  number  of  rolls  that  come  in  contact 
with  the  outside  of  the  felt. 


128  PAPER-MAKING  MACHINES  §6 

201.  Pick-Up  Felts. — If  it  is  desired  to  have  a  felt  pick  up  and 
carry  away  paper  from  another  felt  or  from  a  wire,  a  smooth- 
surfaced  felt  that  is  air-  and  water-tight  is  needed.  Such  a  felt 
must  be  woven  of  fine  wool,  and  it  should  be  napless;  otherwise, 
it  must  be  singed  or  sheared.  A  pick-up  felt  must  be  air-tight; 
therefore,  it  may  be  well  filled  with  sizing.  Trouble  may  often 
be  experienced  with  a  new  pick-up  felt;  when  this  occurs,  fill  up 
the  felt  with  sizing,  which  is  poured  on  until  the  pores  are  filled, 
and  the  pick-up  felt  will  then  do  its  duty. 

Owing  to  the  attention  now  giv^en  by  felt  manufacturers  to  the 
requirements  of  paper  manufacturers,  and  their  mutual  coopera- 
tion, the  paper  maker  need  onlj^  give  the  size  of  his  felt  and  the 
quality  of  the  product  he  is  making. 

202.  Weight  of  Felts.— As  to  the  weight  of  felts  for  different 
qualities  of  paper,  there  is  very  little  information  that  can  be 
accepted  as  a  standard,  because  of  the  different  ideas  of  various 
manufacturers  of  felts  and  paper.  For  instance,  the  weight  of 
felts  made  by  one  manufacturer  for  a  certain  purpose  might  be 
quite  different  from  the  weight  of  felt  made  by  another  manu- 
facturer for  identically  the  same  purpose.  One  manufacturer 
of  felts  for  news  gets  the  best  results  from  felts  weighing  2  ounces 
per  square  foot;  another  manufacturer  could  not  make  a  felt  of 
this  weight  do  the  work  satisfactorily,  and  had  to  make  the 
weight  of  his  felts  2.25  to  2.50  ounces  per  square  foot.  Similarly, 
for  third-press  felts  for  news,  some  manufacturers  get  the  best 
results  from  felts  that  weigh  2.5  to  2.6  ounces  per  square  foot, 
while  others  make  their  third-press  felts  weight  3  ounces  or 
more  per  square  foot.  It  is  a  question  of  durability  and  openness; 
given  the  same  strength  and  durability,  the  lighter  felt  is  more 
open  and  will  give  better  results. 

203.  Qualities  of  Felts. — The  first,  second,  and  third  felts  for 
news  and  wrapping  papers  should  have  qualities  about  as  follows, 
to  obtain  the  best  results: 

First  Felt. — The  first  felt  should  be  of  plain  weave,  made 
open,  well  napped,  weight  about  2  ounces  per  square  foot,  and 
should  be  wo^'en  endless — not  made  endless  by  hand,  as  has  been 
common  practice. 

Second  Felt. — The  second  felt  should  be  the  same  as  the 
first  felt,  except  it  should  be  somewhat  heavier;  weave  like  the 
first  felt,  but  weight  should  be  2.25  ounces  per  square  foot;  this 


§6  THE  PRESS  PART  129 

felt  should  also  be  woven  endless.  After  use  on  the  first  press, 
the  first  felt  is  sometimes  used  as  a  second  felt;  but  if  the  nap  is 
well  worn,  the  paper  may  be  marked. 

Third  Felt. — For  the  third  felt,  a  fine  twill-weave  press  felt 
should  be  used;  weight  should  be  2.75  ounces  per  square  foot;  it 
should  be  well  napped. 

204.  The  Function  of  the  Felt. '— When  a  felt  and  sheet  of 
paper  pass  between  rolls,  the  following  conditions  exist  as  shown 
in  this  diagram.  Felt  A  and  the  wet  sheet  of  paper  B  pass 
between  the  rolls  M  and  N.  As  particular  points,  a  and  a' 
adjoining  on  sheet  and  felt,  move  into  the  nip  of  the  rolls,  a 
position  b  and  h'  is  reached  where  water  will  begin  to  be  squeezed 


out  of  the  paper  and  felt.  From  this  point  on,  the  pressure 
becomes  more  and  more  concentrated,  felt  and  sheet  are  com- 
pressed closer  together  and  water  is  released  from  both  until 
c  and  c'  is  reached  where  the  two  rolls  approach  the  closest  to 
each  other  and  the  greatest  concentration  of  pressure  is  obtained. 
It  will  be  noted,  then,  that  felt  and  sheet  pass  progressively- 
through  rapidly  changing  pressure,  and  that  the  condition  of 
equilibrium  of  this  system  under  a  gradient  of  pressure  dis- 
tribution will  be  determined  b}'^  the  relations  of  many  different 
factors  such  as — 

I.  The  pressure  apphed. 

II.  Hardness  of  rolls. 
III.  Radii  of  rolls. 

IV.  The  speed  of  the  sheet  and  felt. 
'■  [Y.  The  time  of  contact. 
j^VI.  The  resistance  of  the  felt  to  the  flow  of  water. 

It  will  be  seen  in  this  diagram  that  the  water  passes  from  the 

sheet  into  the  felt  and  through  the  felts  throughout  a  gradient 

of  pressure  change.     The  ease  with  which  water  will  flow  through 

the  felt  at  these  different  pressures  is  a  very  important  factor  in 

determining  its  efficiency  as  a  water-remover.     The  openness  or 

1  From  an  article,  illustrated  by  charts,  by  E.  A.  Rees,  in  Pulp  and  Paper 
Magazine  of  Canada,  Feb.  1,  1923. 


130  PAPER-MAKING  MACHINES  §6 

porosity  of  the  felt  has  always  been  recognized  as  a  desirable 
property  of  the  felt.  And  the  resistance  of  the  felt  to  the  flow 
of  water  is  important  in  determining  not  only  the  dryness  of 
the  sheet  but  also  other  effects  that  have  to  do  with  ease  of 
operation,  such  as  crushing  and  blowing. 

It  will  be  noted,  however,  that  there  are  some  discrepancies, 
as  illustrated  by  several  points  that  do  not  fall  exactly  on  the 
line.  The  softness  of  the  fabric  also  affects  the  concentration  of 
the  pressure  upon  the  sheet  of  paper.  Large  variations  in  this 
property  may  so  materially  affect  the  concentration  of  pressure 
as  to  over-balance  the  porosity  effect  in  different  directions. 
For  example,  a  hard,  close  felt  might  give  a  drj'^er  sheet  of  paper 
than  a  soft,  open  felt,  if  the  concentration  of  pressure  is  large 
enough  to  off-set  the  difference  in  porosity. 

It  is  also  quite  interesting  to  note  that  as  the  sheet  and  felt 
approach  closer  to  points  c  and  c',  where  the  rolls  are  in  closer 
contact,  there  is  more  and  more  resistance  to  the  flow  of  water, 
because  of  the  impervious  roll  beneath;  and  there  is  also  the 
tendency  for  the  revolving  roll  to  carry  the  water  back  into  the 
nip.  As  the  water  is  released  farther  back  in  the  nip,  then,  there, 
is  more  and  more  necessity  for  water  to  permeate  through  the 
felt  in  the  direction  contrary  to  its  motion.  This  lateral  or 
backward  porosity  through  a  gradient  of  pressure  change  is  also 
a  factor  in  determining  the  efficiency  of  the  felt  as  a  water- 
remover. 

205.  Felts  for  Particular  Papers. — When  manufacturing  fine 
writings  and  bonds,  the  character  of  the  stock  is  such  that  it  is 
difficult  to  free  it  from  water.  Here  finish  is  the  goal;  hence, 
the  felts  are  of  decidedly  closer  texture  and  are  made  of  finer 
yarns  than  the  common  wet  felts  used  for  newsprint  or  wrapping 
papers.  While  a  newsprint  felt  is  of  a  plain  weave,  the  felts  for 
fine  papers  are  generally  of  a  complex  weave,  the  nature  of 
which  is  to  cause  it  to  act  as  a  compact  carrier  and  as  a  perfect 
filler.  A  fair  estimate  of  the  weights  per  square  foot  for  this 
grade  is  1.46  to  1.64  ounces.  The  second  felt  will  be  heavier 
and  much  closer,  weighing  from  1.56  to  2.68  ounces  per  square 
foot.  The  felt  for  the  last  press,  if  three  are  used,  is  very  thick 
and  it  has  a  very  heavy  nap.  It  must  be  borne  in  mind  that  the 
felt  must  permit  a  perfect  filtering  of  the  water  from  the  sheet; 
otherwise,  the  cost  of  production  will  be  high  on  account  of  the 
excessive  steam  consumption  for  drying. 


§()  THE  PRESS  PART  131 

The  felt  used  on  a  machine  making  the  general  type  of  tissue 
papers  is  a  plain-woven,  rather  close-mesh  fabric,  with  little  or  no 
nap  on  the  top  side.-  In  fact,  many  mills  prefer  that  a  felt  for 
making  tissue  paper  be  singed  on  both  sides,  to  keep  the  fibers 
in  the  sheet  from  adhering  to  the  felt  surface  (picking  up). 
Singeing  keeps  the  nap  that  is  formed  by  the  felting  process  from 
being  drawn  over  the  mesh  of  the  felt  by  the  suction  box  or  roll. 
If  the  under  side  of  the  mesh  is  clogged  by  wool,  the  felt  will  soon 
fill  up  and  get  dirty,  causing  broke  and  many  other  difficulties. 

It  is  needless  to  state  that  the  quality  of  the  wool  used  in 
all  these  felts  is  a  matter  for  the  closest  attention  of  the  felt 
manufacturer. 

DETAILS  OF  PRESS  ROLLS 

206.  Construction  of  Press  Rolls. — In  the  days  when  paper 
machines  were  so  narrow  that  the  attendant  could  almost  reach 
across  them,  the  lower  press  rolls  were  brass  cased  and  the  upper 
press  rolls  were  made  of  wood.  The  nip,  that  is,  the  area  of 
contact  between  the  rolls,  was  very  narrow,  not  only  because 
of  the  absence  of  the  resiliency  and  softness  of  the  rubber  cover- 
ing but  also  because  of  the  small  diameter  of  the  rolls.  A  little 
thought  will  make  it  obvious  that  the  area  of  contact  between 
two  rolls  of  large  diameter  will  be  greater  than  when  the  rolls 
are  of  small  diameter.  Now  the  quantity  of  water  pressed  out 
of  the  paper  is  directly  proportional  to  the  pressure  per  square 
inch  of  area  of  contact  between  the  rolls;  in  other  words,  the 
efficient  working  of  a  press  is  measured  by  the  specific  pressure 
of  the  rolls  (total  pressure  divided  by  the  area  of  contact)  and 
not  by  the  total  pressure.  Pressure  is  frequently  expressed  as 
so  many  pounds  per  inch  of  width  of  the  machine. 

The  custom  of  covering  the  lower  press  rolls  with  rubber  results 
from,  first,  the  necessity  for  an  automatic  adjustment  of  the  line  of 
contact  by  an  elastic  medium,  to  correct  for  faulty  crowning  under 
differing  conditions;  also,  second,  to  prolong  the  fife  of  the  felt. 

207.  Crowning  the  Roll. — Any  beam  will  deflect  (bend)  more 
or  less  between  its  supports,  because  of  its  own  weight;  and  the 
deflection  will  be  increased  by  any  other  load  that  the  beam  may 
support.  The  amount  of  this  deflection  will  depend  upon  the 
material  of  which  the  beam  is  made,  the  diameter  of  the  beam 
(if  round),  and  its  length  between  supports.  But  there  will  be 
a  certain  amount  of  deflection  always;  and  if  the  beam  is  straight 


132  PAPER-MAKING  MACHINES  §6 

and  horizontal,  it  will  sag  in  the  middle  under  its  own  weight 
and  under  a  uniform  load  across  the  beam.  A  roll  in  a  paper 
machine  acts  like  a  beam,  and  its  own  weight  plus  the  pull 
exerted  uniformly  across  it  by  the  felt  cause  it  to  sag  in  the 
middle.  It  follows,  then,  when  two  rolls  are  ground  to  true 
cj'lindrical  surfaces  and  are  placed  one  on  top  of  the  other,  both 
being  horizontal  (or  nearly  so)  and  supported  at  their  ends  (their 
journals),  they  will  not  touch  at  their  middle  points.  This 
condition  is  proved  by  the  fact  that  light  passes  between  the 
rolls;  and  it  can  be  corrected  by  crowning  the  lower  roll  (which 
naturally  sags  the  most)  just  enough  to  insure  perfect  contact 
from  end  to  end.  A  roll  is  said  to  be  crowned  when  it  is  larger 
in  diameter  at  the  middle  than  at  the  ends  and  gradually  tapers 
from  the  middle  to  the  ends.  The  greater  the  diameter  of  the 
roll  in  proportion  to  its  length  the  stiffer  it  is,  and  the  smaller  is 
the  amount  of  sag  (deflection) ;  therefore  there  is  but  little  need 
of  crowning,  if  the  roll  be  large  enough. 

But  there  are  other  considerations  to  be  taken  into  account 
when  choosing  press  rolls  of  large  or  small  diameter  for  a  paper 
machine.  If  the  observer  stand  alongside  a  paper  machine  and 
note  the  escape  of  water  at  the  nip  of  the  press  rolls,  he  will  soon 
be  impressed  with  the  fact  that  the  faster  the  machine  runs  the 
less  chance  the  water  has  to  escape,  because  the  up-coming 
surface  of  the  lower  press  roll  continually  tries  to  carry  the  water 
back  into  the  nip;  and  the  larger  the  diameter  of  the  lower  press 
roll  the  worse  this  condition  becomes.  Attempts  have  been 
made  to  place  water  deflectors  close  to  the  nip,  to  lead  this 
water  awaj^,  and  in  this  service  they  have  been  invariably  suc- 
cessful. In  practice,  unfortunately,  many  accidents  have 
occurred  through  their  use,  such  as  the  deflectors  getting  into  the 
nip,  etc.,  with  the  consequence  that  these  deflectors  are  seldom, 
if  ever  used.  If  a  press  roll  is  made  too  small  in  diameter  and  is 
running  at  high  speed,  it  is  almost  impossible  for  the  machine 
tender  to  pick  off  the  paper. 

'.  208.  Effects  of  Rubber-Covered  Rolls. — When  the  papers 
being  made  on  the  machine  differ  in  weight  and  quality,  the 
amount  of  pressure  on  the  top  roll  is  varied  by  shifting  the  weight 
on  the  levers  that  operate  on  the  journals  of  the  top  roll.  Since 
the  amount  of  deflection  of  the  roll  varies  directly  as  this  pres- 
sure varies,  the  initial  crowning  of  the  rolls  is  not  suited  to  every 
condition  of  working.     The  maximum  efficient  action  of  the 


I 


§6  THE  PRESS  PART  133 

crown  is  possible  only  between  comparatively  narrow  limits  of 
variation  in  position  of  the  weights.  The  use  of  rubber  covering 
largely  increases  the  limits  of  effective  working  pressure  of  a 
particular  crown,  as  compared  with  the  same  crown  on  a  similar 
roll  that  is  not  rubber  covered.  Unfortunately,  the  rubber,  in 
adjusting  itself  to  working  conditions,  largely  increases  the  width 
of  contact  between  the  two  rolls;  this  increases  the  area  of  contact 
and  decreases  the  specific  pressure,  which  lessens  the  de-watering 
action  of  the  press.  In  brief,  the  rubber  covering  of  a  press 
roll  corrects  for  faultj^  crown  and  preserves  the  felts;  but  it  lets 
the  paper  go  to  the  dryers  containing  a  larger  proportion  of 
moisture  than  if  a  plain  roll  were  used;  and  the  softer  the  rubber 
the  more  pronounced  is  this  last  effect. 

Although  having  greater  de-watering  power,  hard  rubber  or 
metal  rolls  possess  the  following  disadvantages:  felt  meshes  fill 
and  become  hard  much  more  quickly;  this  causes  breaks  at  the 
press  due  to  felt  marks  and  to  small  lumps  becoming  crushed 
while  passing  through  the  press;  causes  loss  of  time,  due  to 
frequent  washing  of  felts;  and  it  shortens  the  life  of  the  felt, 
because  of  frequent  washing  and  the  lack  of  cushion  in  hard- 
rubber  covered  rolls. 

210.  Felts  taken  from  a  press  whose  rolls  are  covered  with 
hard  rubber  are  seldom  really  worn  out;  rather,  they  have  lost 
just  enough  of  the  nap  to  make  them  thinner  and  too  hard  to 
give  good  results  with  hard  rolls;  since  thin,  napless  felts  fre- 
quently mark  the  paper.  Two  weeks,  or  12  running  days  of  24 
hours  each,  is  about  the  Umit  of  running  time  for  felts  on  hard 
rolls.  Further,  when  hard  rolls  are  used,  it  is  necessary  to  wash 
felts  at  least  once  every  24  hours. 

If  rubber  of  the  proper  hardness  (density)  be  used,  the  running 
time  of  felts  between  washings  will  be  largely  increased,  and  the 
life  of  the  felts  will  therefore  be  greatly  lengthened;  in  fact, 
felts  may  then  be  used  for  four  or  five  weeks,  or  even  longer. 

If  there  is  a  disadvantage  in  using  soft  rolls,  it  is  because  they 
need  more  frequent  grinding;  a  soft  roll  should  be  ground  about 
once  in  every  two  months.  However,  a  roll  covered  as  stated 
will  easily  give  3  to  4  years'  run,  if  properly  used  and  not  allowed 
to  corrugate. 

211.  Troubles  Peculiar  to  Rubber  Coverings. — A  rubber 
covering  corrugates  or  gets  uneven  in  lines  parallel  to  the  axis 


134  PAPER-MAKING  MACHINES  §6 

of  the  roll,  if  the  rubber  is  subjected  to  too  much  pressure.  This 
effect  is  generally  caused  by  the  roll  being  crowned  either  too 
much  or  too  little,  and  because  the  machine  tender  is  obliged 
to  carry  too  much  weight  on  his  levers  in  order  to  get  an  even 
pressure  between  the  rolls  across  the  machine.  The  longer  Hfe 
of  a  soft-rubber  covered  roll  will  more  than  counterbalance  the 
expense  of  grinding  the  roll,  when  this  is  compared  with  the  loss 
of  felts  and  paper  production  that  are  inevitable  consequences 
of  the  use  of  hard  rolls.  Hard  rolls  have  also  a  further  dis- 
advantage, in  that  they  have  a  decided  tendency  to  check, 
and  these  check  marks,  or  small  cracks,  must  be  ground  out  as 
often,  nearly,  as  the  soft  roll  requires  grinding  to  remove  its 
corrugations. 

The  density  (hardness)  of  rubber-covered  rolls  that  give  satis- 
factory service  should  be  measured  with  a  plastometer,  sclero- 
meter,  or  a  similar  instrument;  the  results  thus  obtained  should 
be  noted  and  should  be  insisted  upon  when  drawing  up  specifica- 
tions for  use  in  ordering  new  rolls. 

Each  maker  indicates  the  density  of  his  rubber  covering  differ- 
ently; thus,  one  maker  indicates  the  density  for  the  first  and 
second  press  rolls  by  4f  and  for  the  third  press  by  5;  another 
uses  A.  11  and  A.3  for  the  same  purpose;  etc.  The  proper 
designations  must  be  obtained  from  the  makers'  catalogs. 

212.  Crown  of  Rolls. — In  general,  it  is  probable  that  too  much 
crown  is  given  the  lower  roll,  the  elastic  quality  of  the  rubber 
covering  being  depended  upon  to  counterbalance  any  irregu- 
larities in  dressing  the  roll. 

The  following  table  gives,  approximately,  the  proper  crown  for 
lower  press  rolls  when  they  are  being  ground;  and  the  values 
here  specified  are  sufficiently  exact  for  all  practical  purposes, 
unless  the  design  of  the  roll  itself  varies  extremely  from  general 
shop  practice.  The  table  gives  the  crowning  for  rubber-covered 
rolls  for  the  first  and  second  press;  for  the  third  press,  reduce  the 
values  5%.  Thus,  for  a  20-inch  roll  for  a  first  or  second  press 
having  180  inches  length  of  face,  the  crowning  is  (see  table)  .104 
inches;  for  a  third  press,  this  should  be  .104  X  (1  —  .05)  =  .104 
X  .95  =  .0988,  say  .099  inches.  The  figures  here  given  for  the 
crowning  indicate  how  much  larger  the  diameter  of  the  roll  should 
be  at  the  middle  than  at  the  ends.  It  is  assumed  that  the  rolls 
are  made  with  cast-iron  bodies  and  that  they  are  of  standard 
construction. 


§6 


THE  PRESS  PART 


135 


o 
u 

S 

s 
N 

•OUiOOOOh-t-OO 
•-<COC0O00t^>O'<»< 

C^     rH     —1     rt 

o 

Oi'S<MC5t^tOiOiJ< 

o 

CO 

t^cooor^coooicooo 

—    tONOOO«Oi.OTj<CO 

O     l-H     ,-H     ^H 

o 

o 

O 

§ 

PI 

l^NOt^OlflTllcOOlo 
O-^'iMt^iO-^COMCI 

< 

o 

ONTl(lOOt>.00   —    «0(N 

coci05t^«)Tj)co«Ne>i 

o 
m 

g 

2Je<5TtiCTiM<-<OCItONO) 

a 

■a* 

o 

CI<--i|^t^Tl<rl<cOr^CIOOO 

t^ciM®u5T)ieoe<i(N«rH 

m 

O 

» 

i 

o^i-ieocoiOh-ooeoostD'i" 
020r->o-*eocicii-i.H« 

g 

OOOOWOCOt^   —    MOJOWrt 

o 

o 

Or-.«Ot^OJt^Oi/5CilO(NOX 

1 

i 

|m§§5mS;2222*'*'-'' 

Q 

< 

a 

o 

§o§^wS!2:22®*''*"'^ 

§ 

1-1 

°«s«S22:;3*'"'*""*" 

fa 

o 

§ 

OOU3C0Oi-(f-if-( 
CI    •-< 

o 

o 
« 

§ 

^   r»   ^  C^  1-*  iM 

g 

o 
CI 

O^J^J-NaicO>OTHWCIIM.-(rt       . 

o 

CO 

CI 

|gOt~j-J«0-u<c<9MCI(N-Hrt      •      • 

o 

00 

eot^ot-iOijtpSN^rt-^     .     .     .     . 

o 

eo 

000»«5^e<S(Ni-lrt 

g 

Cl 

o 

« 

W'^^ 

s 
.s 

CO 

ooofi'<)<(ooooe»'<»<<ooooei^«o 
_rt«rt«ei(Nc<e^e>ie<sMroeo 

136  PAPER-MAKING  MACHINES  §G 

THE  FELT  ROLLS 

213.  Construction  and  Sizes.-^The  shells  of  the  felt  rolls  should 
be  of  such  quality  and  thickness  that,  for  any  specified  diameter, 
thej^  may  have  sufficient  strength  to  withstand  the  strains 
induced  by  the  continuous  reversal  of  stress,  which  is  due  to  the 
turning  of  the  roll  in  the  grip  of  the  pulling  felt.  Consider,  for 
instance,  a  felt  roll  8  inches  in  diameter,  to  be  used  on  a  high- 
speed news  machine.  Such  a  roll  may  revolve  on  its  own  axis 
sa}^  300  times  in  a  minute,  giving  600  reversals  of  stress  in  that 
time.  Some  day,  this  action  must  crystallize  the  metal  at  the 
point  of  greatest  bending  moment,  just  as  a  wire  can  be  broken  by 
continually  bending  it  back  and  forth.  The  life  of  these  rolls 
depends  on  the  selection  of  good  material,  proper  thickness  and 
diameter  of  shell,  and  they  should  be  in  dynamic  balance.  Use 
as  few  rolls  as  possible  on  the  outside  of  the  felt ;  each  is  a  dirt 
catcher,   and  eacli   deposits  dirt  on  the  paper  side  of  the  felt. 

214.  Proper  Balancing  of  Rolls. — A  roll  is  in  static  balance 
(neutral  equilibrium)  when  it  can  be  placed  with  its  axis  hori- 
zontal, its  journals  resting  on  knife  edges,  and  have  no  tendency 
to  roll  or  turn.     A  roll  is  in  dynamic  balance  when  it  turns 


Fig.  62. 

steadily  in  its  bearings  at  high  speed,  A  roll  may  be  in  static 
balance  and  not  in  djmamic  balance,  as  will  now  be  explained. 
Referring  to  Fig.  62,  suppose  A,  B,  C,  and  D  are  weights  placed 
inside  the  shell.  If  A  and  B  are  equal  in  weight  and  shape,  are 
situated  equally  distant  from  the  axis  of  the  roll,  are  placed  on 
opposite  sides,  but  at  opposite  ends,  the  roll  will  be  in  static 
balance.  If  C  and  D  are  of  different  weights  and  shapes,  C 
being  lighter  than  D  and  farther  from  the  axis,  D  may  be  so 
placed  that  the  roll  will  still  be  in  static  balance.  If  the  roll  is 
turning  swiftly  in  its  bearings,  weights  A  and  B  not  being  directly 
opposite  each  other  will  impart  to  the  roll  a  wobbly  motion. 
Since  C  and  D  are  not  of  equal  weight  and  are  situated  at  unequal 
distances  from  the  axis  ^f  re  volution,  the  centrifugal  force  exerted 
by  D  and  the  section  of  the  shell  adjacent  to  D  is  not  quite  the 
same  as  that  exerted  by  C  and  the  section  of  the  shell  adjacent  to 
C.     At  very  high  speeds,  the  difference  between  these  two  values 


§6  THE  PRESS  PART  137 

for  centrifugal  force  becomes  considerable,  and  it  puts  additional 
stresses  and  strains  on  the  roll  and  on  the  bearings.  This  matter 
of  dj'namic  balance  becomes  especially  important  in  connection 
with  Fourdrinier  table  rolls. 


THE  DRAW 

215.  Definition  of  Draw. — At  this  point,  it  is  advisable  to 
consider  the  effect  of  faulty  draws  of  paper  between  the  presses. 
The  draw  is  the  pulling  the  paper  receives  as  it  passes  from  one  pair 
of  rolls  to  another;  for  example,  between  couch  rolls  and  the  first 
press  rolls,  between  the  rolls  of  the  first  and  second  presses,  the 
second  and  third  presses,  last  press  and  dryers,  drj^ers  and  cal- 
ender, and  calender  and  reels.  The  term  is  especially  applicable 
to  the  gaps  at  the  wet  end,  where  the  paper  gets  about  all  of 
its  longitudinal  stretching,  which  is  caused  by  each  press  running 
faster  than  the  one  that  precedes  it. 

216.  Correcting  Faulty  Draws. — If  the  paper  is  too  tight  be- 
tween the  couch  rolls  and  the  first  press,  and  between  the  presses, 
it  may  get  narrow,  even  though  the  deckles  have  not  been 
moved,  and  the  trim  at  the  slitters  may  be  getting  dangerously 
narrow.  In  such  cases,  bring  the  various  presses  more  nearly  to  a 
uniform  speed  by  speeding  up  the  slow  ones  or  slowing  down  the 
fast  ones.  The  trouble  may  have  arisen  through  changing  the 
weights  on  one  press,  or  because  of  a  change  in  character  of  stock. 
Many  paper  makers  are  too  afraid  of  a  slack  draw  between 
presses;  a  slack  draw  is  a  good  thing,  provided  it  is  not  loose 
enough  to  crease  the  paper.  Always  remember  that  the  less 
a  paper  is  stretched  on  the  machine  the  stronger  it  is.  The 
control  of  the  draw  has  been  improved  by  the  development  of  the 
electric  drive,  described  in  Vol.  V. 

Sometimes  a  paper  machine  is  not  quite  in  alinement,  and  the 
paper  may  show  a  tendency  to  travel  to  one  side,  even  arriving 
at  the  calenders  4  inches  or  more  to  one  side.  This  fault  can  be 
corrected  by  putting  a  leading  roll  with  the  proper  "cant," 
obliqueness,  between  the  last  press  and  the  dryers,  thus  guiding 
the  paper  back  again  to  the  center  of  the  dryer  rolls. 

217.  A  Cause  of  Winder  Trouble. — A  great  deal  of  the  trouble 
experienced  with  calenders  and  winders  on  high-speed  machines 
is  due  to  faults  at  the  press  part.  Failure  to  press  the  paper  to  a 
uniform  thickness  is  especially  liable  to  cause  trouble  on  the  uni- 
form speed  reels  and  winders. 


PAPER-MAKING 
MACHINES 

(PART  2) 


EXAMINATION  QUESTIONS 

(1)  Explain  how  the  paper  is  transferred  from  the  wire  to  the 
felt. 

(2)  What  factors  affect  the  percentage  of  solids  in  the  paper  as 
it  comes  to  the  press  part? 

(3)  What  factors  affect  the  percentage  of  solids  in  paper  going 
from  the  press  part? 

(4)  About  what  is  the  limiting  percentage  of  solids  obtainable 
in  paper  by  pressing  in  the  press  part  of  the  paper  machine? 

(5)  (a)  What  is  the  nature  and  purpose  of  the  press-rol)  doctor  ? 
Why  should  it  be  oscillated? 

(6)  (a)  How  is  the  paper  transferred  from  the  first  press  to  the 
second?  (6)  from  the  last  press  to  the  dryers? 

(7)  Why  is  the  paper  reversed  at  the  last  press? 

(8)  Explain  the  purpose  and  operation  of  the  felt  guide  roll? 

(9)  (a)  Describe  a  felt  suction  box?     (6)  What  is  the  advan- 
tage of  using  it? 

(10)  A  press  has  the  following  lever  system? 

(11)  Name  some  advantages  of  a  suction  press  roll. 

(12)  Describe  the  method  of  putting  on  a  new  felt. 

(13)  What  precautions  should  be  taken  when  putting  on  a  felt? 

(14)  (a)  What  is  usually  meant  by  "felt  mark"?  (6)  how  is 
it  remedied? 

(15)  Mention  some  points  on  the  care  of  felts. 

(16)  What  is  the  effect  of  tension  on  felts? 

(17)  What  is  meant  by  crowning  a  roll?  Why  is  it  necessary? 
How  much  crown  is  required  for  a  roll  160  inches  wide  and  24 
inches  in  diameter.  ? 

§6  139 


140  PAPER-MAKING  MACHINES  §6 

(18)  What  is  the  effect  of  incorrect  crown  of  the  press  roll  on  the 
felt? 

(19)  Compare  the  effects  of  small  hard-  and  soft-rubber  rolls. 

(20)  Explain  (a)  the  term  "draw;"  (6)  the  danger  in  a  slack 
draw;  (c)  in  a  tight  draw. 


SECTION  6 

PAPER-MAKING 
MACHINES 

(PART  3) 


THE  DRYER  PART 


SMOOTHING  ROLLS 

218.  Passing  from  Last  Press  to  Dryers. — The  paper  has  now 
been  followed  from  the  breast  roll  of  the  Fourdrinier  part  until 
it  has  passed,  with  its  direction  reversed,  through  the  nip  of 
the  last  press  of  the  press  part.  The  paper  has  been  picked  off 
by  the  machine  tender  and  passed  over  the  paper  roll,  which  is 
carried  by  brackets  on  top  of  the  last  part  of  the  press  rolls.  This 
part,  like  all  other  paper  rolls,  unless  driven,  must  be  set  in  motion 
before  the  paper  is  passed  over  it.  From  this  point,  the  paper  is 
put  through  the  smoothing  press;  or,  if  there  is  no  smoothing 
press,  the  paper  is  passed  directly  into  the  dryer  section,  dryer 
part  or  dryer  nest,  as  it  is  variously  termed.  But  if  the  last  press 
be  not  reversed,  the  paper  comes  straight  through  with  the  felt, 
and  it  can  be  passed  directly  to  the  smoothing  press  or  dryers. 

The  paper  at  this  point  will  contain  60%  to  70%  of  water. 
In  this  condition,  it  requires  less  pressure  to  smooth  out  the 
inequalities  in  the  surface  that  are  due  to  impressions  of  the  wire 
mesh  and  the  weave  of  the  felts  than  when  the  paper  is  dry  and 
hard.  It  is  also  possible  to  print  what  is  practically  a  water- 
mark by  impressing  steel  type  on  the  soft  paper.  Other  designs 
may  be  produced  in  a  similar  manner.  In  some  papers,  the 
impressions  of  the  felt  and  the  bulk  of  the  sheet  are  to  be  retained 
for  special  effects;  but  this  can  be  secured  and  the  paper  flattened 
to  a  uniform  thickness,  by  means  of  a  properly  adjusted  pair  of 
§6  141 


142 


PAPER-MAKING  MACHINES 


§6 


smoothing  rolls,  no  felt  being  used  between  these  rolls.  When 
the  paper  is  finished  at  the  calenders,  there  is  a  greater  likelihood 
of  injuring  the  fibers.  Calender  finishing  depends  more  on 
friction  for  its  results,  and  the  weight  on  the  paper  is  enormously 
greater.  The  smoothing  press  is  most  applicable  to  the  making 
of  book  papers. 

219.  The  Smoothing  Rolls. — Fig.  63  shows  a  pair  of  smoothing 
rolls,  A  and  B,  which  are  mounted  on  the  dryer  frame  at  the  end 
nearest  the  last  press  rolls  K  of  the  press  part.  The  top  press 
roll  A  is  rubber  covered,  while  the  lower  press  roll  B  has  a  gun- 


FiG.  6.3. 


metal  or  bronze  shell.  These  rolls  may' be  so  made  that  they 
can  be  reversed;  that  is,  the  rubber-covered  roll  can  be  placed 
on  the  bottom  and  the  metal-covered  roll  on  the  top.  Some 
paper  makers  prefer  to  have  the  rolls  interchangeable  with  the 
brass  and  rubber  rolls,  respectively,  of  the  wet  press.  It  should 
be  noted  that  wood  (maple)  and  stone  rolls  may  also  be  used. 
The  required  difference  in  hardness  may  also  be  obtained  by 
using  two  rubber  rolls  of  different  degrees  of  hardness.  The 
paper  P  is  shown  as  passing  over  the  top  of  the  upper  roll,  back 
through  the  nip  between  the  two  rolls,  and  from  there  to  the 
first  lower  dryer  D,  against  which  it  is  held  by  the  dryer  felt  F. 
Attention  is  called  to  the  ductor  X,  which  guides  the  paper  into 
the  nip  of  the  smoothing  press;  also,  to  the  doctor  Y,  which 
scrapes  the  paper  off  the  lower  smoothing  roll,  so  it  will  drop 


§6  THE  DRYER  PART  143 

between  the  dryer  felt  and  the  first  lower  dryer  D.  If  desired, 
the  paper  can  be  passed  directly  from  the  last  press  K  through 
the  nip  between  the  two  smoothing  rolls. 

Each  succeeding  unit  of  the  paper  machine  runs  a  little  faster 
than  the  preceding  one,  to  prevent  the  paper  from  running  back 
on  a  roll  and  catching  on  a  doctor.  This  causes  a  draw  (see  Art. 
215,  Part  2)  between  successive  units,  which  requires  careful 
attention  and  is  a  frequent  cause  of  breaks.  Adjustment  is 
made  by  shifting  a  belt  on  a  cone  gear  of  a  mechanical  drive, 
etc.,  or  by  means  to  be  described  later  in  connection  with  an 
electrical  drive. 

220.  Crowning  the  Roll. — The  rubber  roll  is  compressible 
and  resilient,  thus  assuring  a  perfect  contact  across  the  machine, 
if  accurately  crowned  and  covered  with  rubber  of  the  proper 
density.  The  correct  crowns  to  be  used  as  a  guide  in  grinding 
these  rolls  have  been  given  in  Part  2  of  this  Section.  Since  the 
design  of  a  press  roll  varies  in  accordance  with  the  ideas  of  differ- 
ent paper-machine  manufacturers,  the  crowns  there  specified 
may  not  quite  suit  all  makes  of  rolls;  but,  for  the  first  grinding, 
they  are  accurate  enough  to  work  satisfactorily  within  the 
range  of  control  given  by  the  weights  and  levers. 

By  carefully  studying  the  smoothing  press  and  its  functions  as 
here  described,  the  machine  tender  can  form  his  own  opinion, 
in  any  particular  case,  as  to  whether  it  is  better  to  pass  the  paper 
over  the  top  roll  or  directly  through  the  nip,  and  whether  to  have 
the  rubber  or  the  bronze  roll  on  top;  either  change  reverses  the  side 
of  the  sheet  in  contact  with  the  rubber  roll.  In  deciding  such 
matters,  always  take  into  account  the  matter  of  risk  of  injury  to 
the  man  that  passes  the  paper,  and  use  that  arrangement  which 
will  be  the  safer  for  him. 

221.  Finish  of  Paper. — The  whole  question  of  finish  of  paper 
can  be  solved  by  straight  thinking.  First  find  out  what  finish  is 
required,  whether  it  is  to  be  rough,  smooth,  or  glazed.  A 
glazed  finish  is  obtained  by  crushing  the  surface  of  dry  paper  after 
a  superficial  dampening  or  sweating;  a  smooth  finish,  by  the  use 
of  pressure  rolls  or  breaker  calenders  in  the  drj^er  nest.  M.  G. 
or  machine  glazed  paper  is  made  on  a  Yankee  machine,  which 
is  fully  described  in  Vol.  V. 

222.  Adjusting  the  Pressure. — A  method  of  adjusting  the 
pressure  between  the  rolls,  one  that  is  used  quite  generally  on 


144  PAPER-MAKING  MACHINES  §6 

smoothing-press  installations,  is  shown  in  Fig.  63.  At  R,  a 
stationary  revolving  nut,  which  is  usually  turned  by  means  of  a 
ratchet  handle,  is  used  to  bring  the  two  rolls  together.  One 
of  the  rolls  is  covered  with  chalk  and  is  brought  into  contact  with 
the  other  roll  by  means  of  the  two  ratchets,  one  on  either  side  of 
the  machine,  until  no  light  can  be  seen  between  them;  the  rolls  are 
then  separated,  and  the  width  of  the  chalk  mark  that  is  impressed 
on  the  unchalked  roll,  preferably  the  rubber  roll,  will  show  by 
its  character,  whether  even  or  uneven,  the  degree  of  pressure 
between  the  rolls  with  respect  to  uniformity.  If  the  position  of 
the  weights  and  the  position  of  the  screws  with  respect  to  the 
ratchets  be  plainly  marked  by  center-punch  or  chisel  marks  when 
the  transferred  chalk  mark  is  even  all  the  way  across  the  machine, 
then  this  machine  can  be  easily  adjusted  when  running  to  give 
uniform  pressure  when  doing  its  work  as  a  smoothing  press. 

223.  Definition. — There  is  sometimes  a  misunderstanding  as 
to  the  meaning  of  the  words  "ductor"  and  "doctor,"  as  used  in  the 
industry.  In  this  textbook,  the  term  ductor  refers  to  any  device 
for  leading  (conducting)  the  paper  into  a  nip.  The  word 
doctor,  on  the  other  hand,  refers  to  a  scraper  that  is  used  to  keep 
the  surface  of  a  roll  clean. 


A  TYPICAL  DRYER  PART 

224.  Purpose  of  the  Dryers. — The  dryer  section  of  a  paper 
machine  consists  of  a  set  of  cast-iron  cylinders,  connected  and 
driven  by  a  train  of  gears,  and  heated  by  steam,  the  steam  so  used 
being  exhaust  or  low-pressure  steam.  Most  machines  have  a 
dryer  felt  or  canvas,  to  support  and  carrj'^  the  paper  and  hold 
it  in  contact  with  the  cylinders,  which  are  usually  called  the 
dryers.  Heat  from  the  steam  is  conducted  through  the  dryer 
shells  to  the  paper  and  evaporates  the  moisture  (water)  in  the 
paper;  the  resulting  vapor  is  absorbed  by  an  air  current,  and  is 
carried  outside  the  building.  In  passing  over  the  dryers,  the 
moisture  content  of  the  paper  will  be  reduced  from  an  original 
state  of  60%-70%  to  6%-8%  on  leaving  the  dryers;  this  means  the 
removal  of  about  2  pounds  of  water  per  pound  of  finished  paper. 

It  is  necessary  to  provide  means  for  removing  the  moisture- 
laden  air  from  the  room  and,  also,  for  removing  from  the  dryers 
the,water  that  results  from  the  condensation  of  the  steam ;  methods 
for  accomplishing  this  will  be  described  later. 


J 


THE  DRYER  PART 


145 


225.  The  Two  Parts  of  the  Dryer  Section. — ^Fig.  64  shows  a 
typical  dryer  part.  It  consists  of  a 
smoothing  press  A,  30  48-inch  (diam- 
eter) dryers  D,  and  2  36-inch  felt 
dryers  B.  In  this  case,  the  paper  passes 
through  the  smoothing  press,  and  the 
dryers  are  driven  by  gears  at  the  back. 
There  are  two  upper  felts  and  two 
lower  felts.  The  first  upper  felt  and 
the  first  lower  felt  partially  enwrap  the 
first  8  (left-hand)  upper  dryers  and  the 
first  8  lower  dryers,  respectively.  The 
first  upper  felt  and  first  lower  felt  have 
each  a  felt  dryer  B,  an  automatic  guide 
roll  C  (see  also  Fig.  66),  and  an  auto- 
matic stretch  roll  E  (see  also  Fig.  67). 
The  second  upper  felt  and  the  second 
lower  felt  partially  enwrap  the  7  upper 
dryers  and  the  7  lower  dryers,  respect- 
ively, at  the  right  end  of  the  nest  (sec- 
tion); they  both  have  an  automatic 
guide  roll  G  and  an  automatic  stretcher 
F,  but  no  felt  drj'^er.  The  felt  on  the 
first-felt  dryer  is  more  efficiently  placed 
as  shown,  because  the  dryer  felts  are 
damper  at  this  point  than  at  any  other 
place  in  the  dryer  nest,  and  the  dried 
felt  immediately  takes  up  paper  again. 
The  reader  is  advised  to  take  a  pointer 
that  will  not  mark  the  diagram,  Fig.  64, 
(a  knitting  needle  will  do),  and  follow, 
first,  the  run  of  the  felts  throughout  the 
nest;  then  follow,  second,  the  run  of  the 
paper.  Follow  the  run  of  the  felts  first, 
beginning  with  the  lower  felt,  because 
it  first  receives  the  paper.  The  circles 
in  solid  lines  represent  dryers,  the  larger 
ones  in  dotted  lines  are  the  gears. 

226.  Course  of  the  Felts. — Beginning 
with  the  felt  roll  H,  below  the  smooth- 
ing  press,   follow  the  lower  felt  throughout  [its  entire  length 


146  PAPER-MAKING  MACHINES  §6 

until  the  starting  point  is  again  reached.  This  felt  (canvas 
wraps  around  approximately  one-third  of  the  circumference 
of  the  first  (left-hand)  dryer  D.  The  felt  touches  about  one-half 
of  the  surface  of  each  dryer  after  the  first;  it  passes  under  the 
first  four  dryers  and  over  the  first  four  felt  rolls  (not  counting  the 
first  roll  H),  reaching  at  this  point  the  two  rolls  Ri  and  Ro,  over 
the  pinion  P.  As  the  felt  comes  up  from  under  the  eighth  lower 
dryer,  over  the  felt  roll,  and  down  on  its  return  journey,  it  first 
passes  around  a  hand  guide  roll  Ki.  This  last  is  simply  a  felt 
roll,  one  journal  of  which  rests  in  bearings  on  a  bracket,  which  can 
be  moved  by  means  of  a  hand  screw;  the  hand  screw  itself  is 
fixed,  and  it  works  in  a  bracket  base,  as  in  a  nut,  to  move  the 
bracket  in  the  desired  direction.  The  hand  guide  roll  may  be 
located  elsewhere;  in  fact,  it  is  a  principle  that  the  lead  of  a  felt 
to  a  guide  roll  should  be  as  long  as  possible. 

The  dryer  felt  then  travels  back  until  it  comes  to  the  automatic 
stretcher  E,  which  is  more  fully  described  later.  This  stretcher 
automatically  takes  in  the  slack  of  the  dryer  felt  by  means  of 
weights,  which  are  suspended  on  a  carriage,  the  chain  holding  the 
weights  passing  over  a  pulley  that  is  between  the  stretcher  and 
the  weights.  The  position  in  which  the  stretcher  is  here  shown  is 
probably  due  to  some  local  condition  or  some  personal  idea  of 
the  designer;  it  were  better  to  place  it  nearer  the  hand  guide  roll 
or  nearer  the  first  return  of  the  felt,  like  the  stretchers  shown  at 
El  and  Fi  in  the  two  upper  felts,  and  at  F  in  the  second  lower  felt. 

From  the  automatic  stretcher,  the  felt  passes  over  an  auto- 
matic guide  roll  C,  which  is  more  fully  described  later.  This 
guide  roll  has  bearings  on  brackets  that  swing  on  pivoted  levers. 
When  the  felt  travels  too  much  to  one  side,  it  pushes  against  a 
finger  on  the  lever  at  that  side,  which  pushes  the  bearing  forward 
and  forces  the  felt  to  travel  toward  the  other  side.  To  obtain 
sensitive  automatic  action  of  the  guide,  the  distance  between  the 
nearest  roll  back  of  the  guide  roll  and  the  guide  roll  itself  should 
be  at  least  6  feet,  and  preferably  much  greater,  the  best  distance 
being  determined  by  local  conditions. 

After  leaving  the  automatic  guide  roll,  the  felt  comes  to  the 
felt  dryer  B.  Concerning  the  value  of  a  felt  dryer,  there  is  a 
difference  of  opinion.  Insofar  as  dr\'ing  the  paper  goes,  a  felt 
dryer  is  probably  not  the  equal  of  an  extra  dryer  in  the  dryer 
section;  but  dr3Mng  the  felt  is  supposed  to  keep  the  felt  from 
rotting,  and  it  thus  makes  the  felt  last  longer. 


§6  THE  DRYER  PART  147 

In  the  manner  just  outlined,  the  reader  is  advised  to  follow  the 
course  of  the  other  three  felts.  Some  machines  have  only  one 
lower  and  one  upper  felt;  some  have  no  upper  felt,  but  if  the 
dryer  nest  be  driven  as  two  parts,  the  felt  must  be  divided. 

227.  Prevention  of  Accidents. — The  felt  roll  H  under  the 
smoothing  press  is  so  placed  that  the  paper  from  the  smoothing 
press  can  be  easily  dropped  between  the  felt  and  the  first  lower 
dryer  without  any  danger  of  crippling  the  back  tender's  hands. 
A  pony  dryer  or  lead  roll  is  often  used,  and  occupies  the  position 
of  the  smoothing  press.  Too  much  stress  cannot  be  laid  on  the 
necessity  for  extreme  care,  not  only  in  passing  the  paper  through  the 
dryers  but  also  in  considering  and  selecting  the  best  position  for 
the  dryer-felt  rolls  between  the  dryers.  The  danger  points  are 
where  the  back  tender  is  required  to  pass  the  paper  in  between  the 
felt  and  dryer,  when  both  felt  and  dryer  surfaces  are  moving  so  as 
to  draw  the  hand  in ;  the  points  where  the  paper  is  to  be  taken  out 
are  obviously  less  dangerous.  It  is  a  good  thing  to  move  all  the 
felt  rolls  over  as  far  as  practicable,  to  make  the  receiving  angle  as 
wide  as  possible.  No  point  of  machine  efiiciency  should  be  con- 
sidered important  enough  to  warrant  the  increase  of  any  risk  to 
the  operator,  beyond  the  absolute  minimum  obtainable. 

228.  Some  Troubles  and  Their  Remedies. — Troubles  on  a 
machine  can  sometimes  be  remedied  by  increasing  the  lead 
between  the  felt  roll  and  the  guide  roll  in  the  direction  in  which 
the  felt  is  travehng.  If  the  felt  is  getting  wet  after  passing  the 
automatic  stretcher,  and  there  is  a  felt  dryer  on  that  felt,  take 
some  weights  off  the  automatic  stretcher,  thus  avoiding  the 
strain  due  to  any  subsequent  shrinking. 

A  felt  drj^er  that  is  situated  as  in  Fig.  64,  will  tend  to  cause  the 
felt  to  pull  very  strongly  on  the  nearest  felt  rolls.  If  the  felt 
gets  wetted  by  vapors  after  it  leaves  the  automatic  stretcher, 
and  before  it  reaches  the  felt  drj^er,  the  pull  may  be  so  great  as  to 
bend  the  rolls  slightly. 

The  reader  is  advised  to  follow  the  course  of  the  other  three 
felts  shown  in  Fig.  64  in  a  manner  similar  to  that  just  described 
for  the  first  lower  felt. 

229.  Course  of  the  Paper. — The  course  of  the  paper  will  now  be 
followed  from  the  smoothing  press  to  the  spring  roll  N,  around 
which  it  passes  before  entering  the  calenders.  As  the  paper 
leaves  the  smoothing  press,  it  is  dropped  between  the  felt  and 


148  PAPER-MAKING  MACHINES  §6 

the  first  lower  dryer  D,  Fig.  64,  passes  under  the  dryer,  comes 
up  on  the  other  side,  and  a  httle  wad  is  tucked  between  the  felt 
and  the  first  upper  dryer.  After  passing  the  first  upper  dryer, 
it  is  taken  by  the  back  tender  and  passed  to  the  entering  side  of 
the  second  lower  dryer;  it  is  thus  passed  under  each  lower  dryer 
and  up  over  the  next  succeeding  upper  dryer  until  it  leaves  the 
last  upper  dryer  and  is  thrown  up  into  the  top  nip  of  the  calen- 
ders; sometimes  it  is  thrown  over  the  top  roll,  depending  on  which 
side  of  the  stack  the  first  nip  is.  The  spring  roll  A^  automatically 
takes  care  of  variations  in  tension.  The  reader  should  follow  the 
course  of  the  paper  on  Fig.  64,  from  one  end  of  the  dryer  nest  to 
the  other. 

A  very  helpful  device  for  taking  the  tail  over  the  dryers  is  the 
Sheahan  rope  carrier.  This  consists  of  a  pair  of  endless  ropes 
that  are  carried  in  grooves  on  the  front  ends  of  the  dryer  surface. 
They  travel  close  together,  except  where  they  are  made  to 
approach  each  other  at  the  first  dryer  so  as  to  grip  the  end  of  the 
tail  placed  between  them.  The  back  tender  follows  the  paper 
along,  so  as  to  pass  it  b}'^  hand  in  case  of  a  break.  In  another 
patented  device,  compressed  air  is  used  to  pass  the  paper  from 
dryer  to  dryer,  and  from  the  last  dryer  to  the  calenders. 

Doctors  are  sometimes  used  on  dryers  to  prevent  the  paper 
from  winding  round  them. 

230.  Steam  Joints  and  Driving  Gear. — Fig.  65  is  a  cross- 
sectional  view  of  the  dryer  nest  shown  in  Fig.  64.  The  felt  rolls 
R,  the  felt  dryers  B,  the  top  and  bottom  dryers  D,  D,  all  have 
the  same  reference  letters  as  the  corresponding  parts  in  Fig.  64. 
The  steam  joints  M,  shown  connected  to  the  back  hollow  journals 
J  of  the  dryers,  are  piped  to  two  pipe  headers  *S  and  E.  The 
larger  pipe  S  supplies  steam  to  the  dr3'er,  while  the  smaller  pipe 
E  is  Si  drain  that  carries  away  the  water  of  condensation.  The 
steam  joints  are  described  later. 

The  gears  that  drive  the  dryers  are  shown  at  G,  and  a  platform 
or  walkway  for  the  operators  is  shown  at  K.  In  this  case,  the 
felt  dryers  B  are  driven  by  the  felt,  and  they  have  no  gears;  this  is 
good  practice,  but  the  bearings  must  be  kept  in  first-class 
condition. 

231.  Dryers  to  Be  Kept  Free  from  Water,  Air  and  Grease. — It 

is  essential,  in  order  to  dry  paper  well  and  evenly  all  over,  that 
the  dryers  be  kept  free  from  water,  air,  and  grease.     An  air  valve 


§0 


THE  DRYER  PART 


149 


on  the  front  head  of  the  dryer,  which  may  be  a  small  pet  cock, 
will  prevent  accumulation  of  air,  if  opened  at  intervals.  The 
air  acts  as  a  blanket,  to  prevent  heat  getting  to  the  dryer  shell. 
The  water  that  collects  in  the  dryer,  because  of  the  condensation 
of  the  steam,  is  emptied  by  either  a  siphon  or  a  dipper,  as  will  be 


Fig.  65. 


described  later.     Some  heating  systems  are  designed  to  sweep 
the  air  out  of  the  dryers  by  circulation  of  steam. 

The  dryer  part  should  be  started  turning  over  before  any 
steam  is  admitted  into  the  dryers,  in  order  to  prevent  the  unequal 
strains  that  are  produced  when  hot  steam  enters  a  cold  dryer 
that  contains  a  body  of  cold  water  in  its  bottom ;  in  such  a  case, 


150  PAPEIMVIAKING  MACHINES  §6 

the  top  of  the  diyer  heats  and  expands  more  than  the  bottom, 
and  thus  tends  to  get  out  of  shape. 

Oil  acts  as  a  coating,  on  the  inside  of  the  dryer,  preventing 
transfer  of  heat;  it  may  get  into  the  steam  from  the  lubrication 
of  the  engine  piston  and  should  be  caught  in  an  oil  separator. 
If  it  gets  into  the  dr3'er,  it  nia}'  be  nnnovcd  by  treatment  with  a 
hot  solution  of  soda  ash. 


DETAILS  OF  DRYER  PART 


GUIDING  THE  FELT 

232.  General  Principle.— On  all  carrying  rolls,  the  felt  will 
come  to  the  side  that,  the  felt  touches  first,  regardless  of  whether 
the  roll  be  inside  or  outside  of  the  felt.  If  one  end  of  any  roll  be 
moved  toward  the  direction  of  travel  of  the  felt,  the  felt  will 
come  toward  the  end  so  moved;  except,  that  if  the  moving  of  the 
end  of  the  roll  causes  the  roll  to  stop  or  causes  its  speed  to  slacken 
until  the  speed  of  the  roll  is  slower  than  that  of  the  felt,  the  felt 
will  then  slide  the  other  way.  All  guide  rolls  should  be  provided 
with  a  swivel  box  on  the  end  opposite  the  end  of  the  roll 
moved.  Ordinary  carrying  rolls  should  not  be  moved  very  far 
out  of  alinement. 

233.  Automatic  Guide  for  Dryer  Felts. — A  typical  design  for 
an  automatic  guide  for  dryer  felts  is  shown  in  Fig.  66.  The  felt 
on  its  way  from  the  felt  roll  R  passes  under  the  rod  S  and  over 
and  between  the  two  fingers  F,  F.  These  fingers  are  attached 
to  the  rod  S  by  small  clamps  and  bolts,  as  shown,  and  can  be 
moved  along  this  rod  in  order  to  adjust  the  distance  between 
them  to  suit  different  widths  of  felts.  When  the  felt  is  running 
straight  and  the  fingers  are  properly  spaced,  about  ^  inch  farther 
apart  than  the  width  of  the  felt,  the  outside  edges  of  the  felt  will 
not  touch  the  inside  of  the  fingers,  but  will  pass  through  freely. 
The  fingers  hang  downwards,  as  shown  in  view  (6),  and  they  are 
of  sufficient  length  to  partly  support  the  felt  as  it  passes  over 
them.  When  the  felt  begins  to  travel  out  of  line,  it  will  touch 
and  push  against  one  of  the  fingers,  say  at  a,  view  (6),  and  this 
will  cause  one  end  of  the  bell-crank  lever  KL  to  move.  This 
lever  turns  easily  on  the  pointed  pivots  P,  which  are  supported 
by  the  brackets  B,    The  arms  L  carry  the  bearings  E  for  the 


§6 


THE  DRYER  PART 


151 


ends  of  the  felt  roll  on  which  the  felt  travels.  The  arms  K  are 
connected  by  the  cross  shaft  *S;  hence,  in  the  case  of  the  felt 
traveling  toward  either  side,  the  felt  roll  is  moved  by  this  action, 
one  journal  of  the  I'oll  being  advanced  and  the  other  being  pulled 
back,  in  proportion  to  the  effort  made  bj^  the  felt  to  get  out  of 
line.  A  roll  always  tends  to  move  any  body  touching  it  in  a  line 
perpendicular  to  its  axis;  consequently,  the  automatic  stretch 
roll  here  described  acts  to  force  the  felt  to  correct  its  own  errors 
of  travel  and  keep  it  in  line.     It  will  be  noticed  that  the  journal 


Fig.  66. 

of  the  guide  roll  that  is  on  the  side  toward  which  the  felt  is 
traveling  is  always  advanced,  while  the  journal  on  the  other  side 
of  the  machine  is  simultaneously  pulled  back.  As  the  result  of 
this  action,  the  guide  roll  is  quickly  shifted  by  the  felt  when  it 
runs  out  of  line,  and  in  such  a  manner  that  the  axis  of  the  roll  is 
thereby  made  perpendicular  to  the  direction  the  felt  must 
travel  to  correct  its  own  error. 


STRETCHING  AND  TIGHTENING  FELTS 

234.  Automatic  Stretcher  for  Dryer  Felts. — An  automatic 
dryer-felt  stretcher  is  shown  in  Fig.  67.  The  felt  F  is  wrapped 
half  way  around  a  felt  roll  R,  whose  journal  runs  in  a  bearing 
that  is  carried  by  trolley  wheels  C,  a  similar  journal,  bearing,  etc. 


152 


PAPER-MAKING  MACHINES 


§6 


being  on  the  other  end  of  the  roll.  The  trollej's  C  on  either  side 
of  the  machine  are  caused  to  move  simultaneously  by  the  shaft  S, 
which  extends  across  the  machine.  Therefore,  when  pulleys  A 
and  B  on  one  side  turn,  the  corresponding  pulleys  on  the  other 
side  turn  also;  and  they  turn  the  same  distance  at  the  same  time, 
because  all  these  pulleys  are  keyed  to  the  shaft  S.  This  device 
keeps  one  end  of  the  stretcher  roll  from  being  pulled  ahead  of  the 
other,  and  thus  shifting  the  felt. 

The  weights  W,  which  are  hung  on  chains  D  that  grip  the  chain 
slots  on  pulleys  A  on  both  sides  of  the  machine,  tend  to  turn 
shaft  S  with  a  force  that  is  proportional  to  the  number  of  weights 
hung  on  these  chains;  and  they  are  generally  so  calculated  as  to 


A-B  B   A 


^W 


Fig.  67. 


give  a  pull  of  about  2  pounds  per  inch  of  width  of  felt.  The  pull 
of  the  weights  on  pullej^s  A  tends  to  turn  shaft  S,  and  also  pulleys 
B,  which  are  at  the  ends  of  the  shaft  in  line  with  the  trolleys  C. 
The  chains  on  the  trolleys  are  furnished  with  turn  buckles  K,  to 
permit  of  accurate  adjustment.  The  chains  are  also  attached 
to  the  rims  of  pulleys  B;  so  that,  as  these  pulleys  tend  to  turn, 
the  chains  pull  on  trolleys  C  and,  therefore,  on  the  felt  that  is 
wrapped  around  the  felt  roll  carried  by  trolleys  C.  The  trolleys 
move  easily  on  the  guide  rails  T\  and  when  the  pull  of  the  felt 
slackens,  the  weights  automatically  pull  on  the  trolleys  until  the 
proper  tension  is  obtained. 

235,  Felts  Should  not  be  too  Tight  or  too  Loose. — The  machine 
tender  should  form  the  habit  of  watching  the  automatic  felt 
tightener,  to  observe  its  condition;  if  in  good  condition,  this  will 
be  indicated  by  a  constant  movement  in  one  direction  or  the 
other.  If  the  tightener  always  remain  still,  it  should  be  examined ; 
it  is  then  probably  out  of  order  and  may  require  lubricating,  or  it 
may  be  gripped  between  the  rails,  or  the  chains  may  have  shpped 
off  the  pulleys.  If  the  automatic  stretch  roll  does  not  work 
properly,  report  it  to  the  millwright.  A  felt  that  is  too  tight  or 
too  loose  will  spoil  paper  very  quickly,  causing  uneven  drying  and 


§6  THE  DRYER  PART  153 

cockling;  since  the  felt  rolls  may  be  pulled  out  of  line,  if  the  felt 
is  too  tight,  or  the  felt  may  be  hanging  loose  because  the  slack 
is  not  being  taken  up. 

The  old-fashioned  felt  tightener  did  not  have  sufficient  capacity 
to  take  up  all  the  slack  in  a  long  felt.  This  type  of  stretcher  is 
still  used  on  dryer  felts,  and  it  will  take  up  a  certain  amount  of 
slack;  but  it  is  necessary  to  install  also  a  hand-stretching  device 
that  is  similar  in  design  to  the  hand  felt  stretcher. 

236.  The  Dancing  Roll.— A  very  sensitive  and  direct-acting 
stretcher  for  a  dryer  felt  is  a  dancing  roll ;  this  rests  in  a  loop  of  the 
felt,  the  entire  weight  being  carried  by  the  felt.  Brackets  are 
bolted  to  the  dryer  frames,  and  the  bearings  of  the  roll  are  free 
to  move  up  and  down  the  vertical  slots  in  the  brackets.  The 
"return"  felt  rolls,  over  which  the  felt  runs  to  make  the  loop,  are 
supported  in  brackets  bolted  to  the  slotted  brackets.  This  is  a 
good  type  of  dryer-felt  stretcher;  its  principal  failing  is  that  it  is 
limited  in  its  range  of  action  by  the  height  of  the  vertical  slots  in 
the  brackets.  Another  drawback  is  that  one  end  may  get  into  a 
higher  position  than  the  other,  which  w^ould  cause  the  roll  to  act 
like  a  guide  roll  and  shift  the  felt  to  one  side  of  the  machine. 

237.  Amount  of  Stretching  and  Shrinking. — The  purpose  of  the 
automatic  stretcher  is  to  take  up  the  slack  of  the  felt  when  the 
paper  leaves  the  machine  for  any  cause,  as  a  break  at  the  wet  end 
or  a  shut  down.  A  60-yard  felt  will  shrink  3  feet  at  the  very 
least  when  it  is  wet,  and  it  lengthens  a  like  amount  in  a  few  minutes, 
when  the  paper  is  off  the  dryers.  On  the  average,  a  brand  new 
felt  will  shrink  and  stretch  considerably  more  than  this,  some 
felts  as  much  as  6  feet.  The  old-stjde  swing  stretcher  did  not 
give  enough  leeway  to  take  care  of  this  shrinkage;  and  if  the  felt 
were  tightened  up  sufficiently  to  run  straight  and  guide  properly, 
it  was  too  tight  when  it  became  wet. 

After  putting  on  a  new  felt,  it  should  be  weighted  down  until 
it  is  fairly  tight;  and  it  should  be  run  around  a  few  minutes 
before  passing  the  paper  over  it,  to  let  the  felt  straighten.  After 
the  felt  is  perfects  straight  and  the  paper  is  passed  over  the 
machine,  the  machine  tender  should  watch  the  automatic  stretcher, 
to  see  that  it  is  easing  up  as  the  felt  gets  shorter.  If  the  felt  is 
getting  crooked,  it  is  a  sign  that  there  are  not  enough  weights,  for 
a  slack  felt  will  almost  always  run  crooked.  When  a  good  auto- 
matic stretcher  is  in  proper  workingorder  and  is  well  adjusted,  the 


154 


PAPER-MAKING  MACHINES 


§6 


stretch  roll  should  tremble — move  back  and  forth  slightly — 
every  time  the  dr3^er-felt  seam  passes  over  it. 

238.  Guiding  Felts  by  the  Stretch  Roll. — Some  stretchers 
stretch  with  the  felt,  i.e.,  move  in  the  direction  of  travel  of  the 
felt;  others  move  in  the  opposite  direction. 

To  show  how  the  stretch  roll  may  be  used  to  guide  the  felt, 
consider  Fig.  68,  in  which  either  A  ov  B  maj^  be  the  stretch  roll ;  if 
A  be  the  stretch  roll,  then  B  is  the  reef,  or  fixed,  roll,  and  vice 


Fig.  68. 


versa.  Suppose  the  felt  to  be  travehng  in  the  direction  indicated 
by  the  arrows,  that  T  is  the  tight  side,  and  that  S  is  the  slack  side. 
If,  now,  the  roll  A  be  shifted  toward  the  tight  side,  so  its  axis 
EF  makes  an  angle  FEF'  with  its  former  position,  the  felt  will 
go  to  the  slack  side,  in  the  direction  of  the  arrow  H;  but  if  B  be 
shifted  toward  the  tight  side,  so  its  axis  CD  makes  an  angle  DCD' 
with  its  former  position,  the  felt  will  go  to  the  tight  side  in  the 
direction  of  the  arrow  K.  The  roll  A  acts  just  like  the  carrying 
rolls  mentioned  in  Art.  232,  while  B  checks  in  the  opposite 
direction.  The  felt  traveling  from  the  under  side  of  A  to  5 
does  not  count  in  this  connection. 

The  dryer-felt  stretcher  is  one  of  the  most  important  parts  of 
the  machine  to  know  how  to  handle.  If,  for  any  reason,  the  felt 
gets  beyond  control  and  gets  partly  off  the  machine,  moving 


§6  THE  DRYER  PART  155 

the  stretcher  2  inches  out  of  hne  will  guide  the  felt  more  quickly 
and  surely  than  all  the  carrying  rolls  together. 

The  wet  felts  or  woolen  felts  will  always  go  to  the  slack  side  of 
the  stretcher,  except,  very  rarely,  in  the  case  of  a  new  felt,  which 
may  go  to  the  tight  side  for  a  few  hours. 

Dryer  canvas  felts  are  not  made  endless.  Wool  dryer  felts, 
sometimes  used  on  ver\^  fine  paper,  are  made  endless.  Many 
European  machines  use  endless,  wool  dryer  felts. 


REMOVING  AIR  AND  WATER  FROM  DRYERS 

239.  Necessity  for  Removing  Water. — It  was  stated  in  Arts. 
224  and  231  that  the  steam  in  the  dryers  is  continually  condensing 
into  water  as  the  paper  passes  over  the  dryers.  The  water  that 
collects  in  the  dryers  must  be  removed,  since  the  presence  of  even 
a  small  quantitj^  of  water  prevents  the  quick  and  uniform  drying 
of  the  paper.  Two  methods  are  employed  for  getting  rid  of  this 
water:  in  one,  dippers  or  scoops  are  attached  to  the  dryer  and 
turn  over  and  around  with  it,  scooping  up  the  water  to  the  center, 
from  whence  it  flows  out  of  the  hollow  journal;  in  the  other,  a 
siphon,  which  remains  stationary  and  dips  down  to  the  bottom  of 
the  dryer,  is  used. 

240.  Dippers. — Both  dippers  and  siphons  require  some  form 
of  stuffing  box  or  steam  joint  on  the  end  of  the  journal,  to  admit 
steam  into  the  dryer  and  let  out  water  without  loss  of  steam  or 
leakage  of  water. 

Fig.  69  shows  a  dryer  fitted  with  a  steam  joint,  a  double  dipper, 
and  an  interior  steam  distributing  pipe  P,  which  is  so  perforated 
that  the  entering  steam  is  distributed  to  all  parts  of  the  dryer. 
The  two  dippers  D  are  formed  of  open  channel  irons,  of  such  a 
shape  and  bolted  to  the  dryer  head  H  in  such  a  manner,  that  they 
scoop  up  the  contained  water,  when  the  dryer  revolves  in  the 
direction  indicated  by  the  arrow.  The  water  enters  the  open  end 
of  the  scoops;  and,  as  they  are  raised  by  the  turning  of  the  dryer, 
the  water  that  is  scooped  up  flows  along  the  channel  and  is 
dumped  into  the  receiving  chamber  C.  This  chamber  is  a  cast- 
iron  receptacle,  so  equipped  with  baffles  and  guides  inside  as  to 
guide  the  in-coming  water  in  such  a  way  that  it  is  forced  out 
between  the  inside  of  the  rear  journal  J  and  the  outside  of  the 
steam  pipe  P.     When  the  water  reaches  the  steam  joint,  it  flows 


156 


[PAPER-MAKING  MACHINES 


§6 


out  through  passages  E  into  the  pipe  W,  and  from  thence  on  to  the 
main  drain  pipe  below.     In  the  front  head  is  a  manhole  M;  T  is 

a  pet  cock,  which  allows  the  escape 
of  air  when  starting  up,  and  breaks 
the  vacuum  when  shutting  down  over 
Sunday.  Air  is  a  good  non-conductor 
of  heat;  and  if  it  be  not  removed,  it 
will  make  a  blanket  next  the  inside 
of  the  shell  and  prevent  efficient 
transfer  of  heat  and  drying  of  the 
paper.  The  air  vent  is  sometimes  put 
in  the  cap  of  the  front  journal  K, 
which  is  then  drilled  through. 

241.  Another  type  of  dipper  extends 
in  sections  across  the  dryer,  and  is 
attached  to  the  dryer  shell.  Its  oper- 
ation can  be  compared  with  the  action 
of  scooping  up  water  in  a  dustpan  and 
raising  it  until  the  water  runs  down 

=  the  handle  and  into  one's  sleeve,  the 
'i  sleeve  corresponding  to  a  pipe  that 
carries  the  water  off.  The  pipe  that 
receives  the  water  from  the  scoop  is 
horizontal;  it  extends  through  the 
center  of  the  dryer,  and  it  conducts  the 
water  to  the  steam  joint.  It  is  obvious 
that  a  dipper  cannot  work  when  the 
dryer  is  stationary;  but  the  steam 
continues  to  condense,  whether  the 
dryer  is  stationary  or  not. 

242.  Siphons. — One  end  of  a  dryer 
F  is  shown  in  Fig.  70;  it  is  equipped 
with  a  siphon  Ki.  The  steam  inlet 
is  shown  at  H;  K  is  the  water  (con- 
densed steam)  outlet,  and  G  is  the 
stuffing  box  and  steam  joint.  As  be- 
fore stated,  the  siphon  remains  station- 
ary while    the  dryer  revolves.     The 

lower  end  of  the  siphon  pipe  must  clear  the  bottom  of  the  dryer 
at  least  half  an  inch,  in  order  to  make  certain  that  the  dryer  clear 


§6 


THE  DRYER  PART 


157 


the  pipe  as  it  turns;  this  keeps  foreign  substances  from  collecting 
and  catching  the  siphon  pipe,  thus  forcing  it  to  turn  with  the 
dryer.  Sometimes  the  pipe  is  carried  around  and  left  sticking 
up  instead  of  down.  The  siphon  pipe  here  shown  is  not  of  good 
design,  because  the  sharp  bend  in  it  does  not  allow  of  the  pipe 
being  put  in  or  pulled  out  through  the  journal.  A  longer  pipe, 
one  that  reaches  nearly  to  the  other  end  of  the  drj^er  in  a  long, 
gentle  curve,  could  be  inserted  and  withdrawn  readil}^,  and  with- 
out removing  the  head. 


Fig.  70. 


When  the  bottom  end  of  the  siphon  is  covered  with  water,  the 
higher  pressure  in  the  dr^-er  is  exerted  on  the  surface  of  the  water, 
forcing  it  up  through  the  siphon  and  out  through  the  hollow 
journal. 

243.  Comparison  of  Dippers  and  Siphons. — There  is  a  great 
diversity  of  opinion  as  to  the  relative  merits  of  siphons  and 
dippers.  It  is  a  matter  of  fact,  however,  that  both  low-speed 
and  high-speed  machines  are  running  satisfactorily  when 
equipped  with  either  siphons  or  dippers.  In  any  comparison  of  the 
two,  it  should  be  kept  in  mind  that  the  essentials  of  any  good 
drying  system  are  to  keep  the  dryers  free  of  air  and  of  condensate, 
and  to  prevent  the  escape  from  the  machine  of  uncondensed 
steam.     The  dippers  fill  the  last  two  requirements  perfectly, 


158  PAPER-MAKING  MACHINES  §6 

because  they  will  pick  up  water  and  discharge  it  from  the  dryers 
to  a  trap;  but  some  other  means  must  be  provided  for  getting 
the  air  out  of  the  dryers.  In  many  cases,  air  cocks  are  placed 
on  the  face  of  the  dryers  or  are  tapped  into  the  ends  of  the 
journals,  which  are  drilled  for  this  purpose.  Siphons,  on  the 
other  hand,  require  a  steady,  continuous  pressure  drop  between 
the  inside  of  the  dryer  and  the  water  header  in  order  to  lift  the 
condensate  from  the  dryer;  therefore,  a  more  complicated 
arrangement  is  needed  to  prevent  the  loss  of  uncondensed  steam, 
as,  for  example,  special,  individual  air-vented  traps  or  a  circu- 
lating system,  both  of  which  arrangements  are  described  later. 
The  siphon  is  the  ideal  method  of  removing  air  from  the  dryer. 

The  modern  open-trough,  double  dipper  is  probably  as  satis- 
factory as  any  design  of  dipper  for  removing  water.  But,  since 
a  dipper  is  a  revolving  part  of  the  machine,  it  must  be  balanced ; 
also,  great  care  must  be  taken  that  neither  a  dipper  nor  a  siphon 
become  loose,  and  thus  be  a  noisy,  useless  nuisance,  rattling 
around  inside  the  dryer. 

It  should  be  noted  that  there  is  a  critical  speed  of  dryer,  at 
which  the  water  is  kept  thrown  against  the  inside  of  the  dryer 
shell  by  centrifugal  force,  lying  in  a  comparatively  uniform 
layer  over  the  whole  inside  of  the  cylindrical  surface. 

Dippers  will  operate  successfully  in  48-inch  dryers  up  to  a 
paper  speed  of  600  feet  per  minute,  and  siphons  to  nearly  this 
speed.  For  higher  speeds  of  paper,  dryers  of  larger  diameter 
should  be  used. 

244.  The  Steam  Joint. — The  rubbing  surfaces  of  the  moving 
and  stationary  parts  of  the  steam  joint  are  shaped  like  a  ball 
fitting  into  a  socket.  The  ball  is  ground  into  the  socket  until 
only  a  slight  pressure  on  the  ball  will  make  the  joint  both  water 
tight  and  steam  tight.  The  shape  of  this  joint,  see  Fig.  70, 
allows  the  part  of  the  joint  that  is  bolted  to  the  hollow  journal 
of  the  dryer  to  turn  with  the  dryer,  and  its  ball-like  end  fits 
snugly  while  turning  in  the  cup-hke  socket  of  the  part  of  the 
joint  that  is  attached  to  the  piping.  These  joints  should  be 
tight  when  the  side  bolts  joining  the  two  parts  are  only  a  little 
more  than  hand  tight.  If  the  joint  is  not  steam  tight  when  given, 
say,  a  quarter  of  a  turn  of  the  wrench  over  hand  tightness,  it 
should  be  taken  off  at  the  end  of  the  week,  when  shutting  down, 
and  re-ground.  These  joints  can  be  tightened  so  hard  as  to  stop 
the  paper-machine  engine. 


§6  THE  DRYER  PART  159 

If  the  surfaces  of  the  ball-and-socket  joint  are  scored  by  grit  or 
other  foreign  matter,  the  joint  must  evidently  be  re-ground 
before  it  can  again  give  good  service.  When  first  installed, 
steam  joints  are  sometimes  equipped  with  springs,  which  are  so 
proportioned  as  to  take  care  of  a  maximum  of,  say,  20  pounds 
per  square  inch;  but  new  springs  must  be  furnished  that  are 
suitable  for  higher  pressures,  when  a  higher  pressure  will  ulti- 
mately be  used  on  the  dryers.  The  springs  should  never  come 
coil  on  coil,  as  such  a  condition,  when  cold,  would  induce  a  very 
powerful  drag  or  brake  on  the  dryer  when  the  spring  became 
heated. 

245.  Lubricating  the  Joint. — The  lubricant  best  suited  to  a 
steam  joint  should  have  sufficient  body  to  keep  the  rubbing 
surfaces  free  from  contact  with  each  other  under  the  maximum 
pressure;  but  it  should  possess  the  greatest  fluidity  possible  under 
these  conditions.  It  should  also  have  a  high  temperature  of 
decomposition,  and  should  be  free  from  all  tendenc}^  to  corrode 
the  surface  of  the  metal.  The  writer  has  found  a  good  grade  of 
cylinder  oil  to  be  most  satisfactory. 

Never  put  waste  in  the  oil  pans,  because  it  is  then  impossible 
to  tell  whether  the  oil  hole  is  open  and  the  joint  being  lubricated 
or  whether  the  waste  is  merely  being  oiled.  If  the  pressure  on 
the  moving  surfaces  of  a  steam  joint  is  too  great,  i.e.,  if  the 
joint  is  too  tight,  the  joint  acts  as  a  brake  of  considerable  power; 
and  if  the  machine  tender  allows  the  steam  joints  to  be  tightened 
every  time  they  leak,  instead  of  re-packing  or  repairing  them, 
he  is  not  only  wearing  out  the  joints  but  he  is  also  putting  an 
unnecessarj'  load  on  the  driving-shaft  belts  and  the  engine,  thus 
wearing  out  equipment  and  wasting  power. 


OPERATION  AND  MANAGEMENT  OF  DRYERS 


CONTROLLING  THE  STEAM  SUPPLY 

246.  Conditions  for  EflBlcient  Operation  of  Dryer  Part. — The 

dryer  part  depends  on  three  principal  factors  for  its  efficient 
operation:  first,  on  the  arrangement  of  the  piping  that  supplies 
steam  and  removes  condensation  from  each  dryer;  second,  and 
this  is  almost  as  important,  on  the  proper  control  of  the  felt 
tension;  third,  on  the  proper  supply  of  dry  air  in  the  right  place  to 


160 


PAPER-MAKING  MACHINES 


§6 


carry  away  the  water.  Probably  most  of  the  moisture  (water) 
leaves  the  paper  between  the  dryers,  not  while  covered  with  the 
felt.  The  slight  pressure  of  the  moist  air  next  the  paper  when 
so  covered  is  relieved  on  contact  with  the  air,  and  opportunity 
is  given  for  the  evaporating  moisture  to  be  absorbed. 

247.  Necessity  for  Having  Free  Circulation  of  Steam. — The 

main  object  to  be  aimed  at  in  piping  up  the  drj-ers  is  to  keep  up  a 
free  circulation  of  the  steam.  Steam  is  a  non-conductor  of 
heat;  and  since  a  stationary  body  of  steam  transmits  heat 
slowly,  by  convection,  the  outside  of  such  a  body  of  steam  may 
lose  a  large  part  of  its  heat,  while  the  inside  remains  at  nearly 
its  original  temperature.  To  maintain  a  constant  supply  of 
heat,  which  will  give  a  uniform  temperature  across  the  face  of  the 
dryer  and  thus  insure  uniform  drying  across  the  sheet  of  paper, 
it  is  necessary  to  keep  the  steam  on  the  move  inside  the  dryer 
shell.  To  accomplish  this,  there  must  be  a  difference  in  pressure, 
which  should  be  about  half  a  pound  per  square  inch  between 
the  steam  header  and  the  dryer  and  another  half  pound  between 
the  drj'er  and  the  water  or  drain  header. 

248.  A  Steam-Pressure  Controlling  System. — One  method  of 
obtaining  approximately  these  conditions  and  forcing  circulation 


Q(I)(IlQQ(D(^X^X^M 


of  steam  is  indicated  in  Fig.  71.  The  steam  header,  or  supply 
pipe,  is  shown  divided  into  two  sections  by  distributing  valve  3, 
both  sections  being  again  divided  by  two  other  distributing 
valves  3,  so  the  proportion  of  steam  to  each  section  can  be 
controlled.  The  exhaust  steam  from  the  engine  passes  through 
the  diaphragm-operated  valves  2,  which  are  automatically 
controlled,  so  that  the  total  quantity  of  steam  to  the  dryer  nest  is 
varied  in  accordance  with  the  pressure  in  the  dryers.  If,  in 
drying  the  paper,  more  steam  than  usual  is  condensed,  thus 


§6  THE  DRYER  PART  161 

causing  the  pressure  in  the  dryers  to  drop,  this  causes  the  dia- 
phragm to  open  valve  2  and  let  more  steam  into  the  system. 
If  the  steam  pressure  in  the  dryers  gets  too  high,  this  diaphragm, 
which  is  controlled  by  air  pressure,  shuts  valve  2,  and  the  steam 
pressure  is  brought  back  to  normal.  The  steam  that  is  admitted 
through  valve  2  is  distributed  to  the  two  ends  of  the  dryer  part, 
in  the  proportion  desired,  by  valves  3,  which  are  adjusted  by  the 
operator. 

The  water  header  is  divided  into  four  parts,  the  three  flanges 
13  being  blanks;  this  is  done  to  keep  the  pressure  in  the  water- 
header  sections  from  getting  so  high  as  to  exceed  the  steam 
pressure  in  any  dryer.  With  a  piping  arrangement  of  this  kind, 
by  changing  the  pressure  in  the  water  header,  the  paper  maker 
can  have  more  pressure  in  any  one  of  the  four  sections  of  the 
dryer  part  than  in  any  of  the  others ;  at  the  same  time,  the  steam 
in  the  higher  pressure  part  cannot  escape  through  the  water 
header  and,  by  thus  communicating  with  the  others,  raise  the 
pressure  in  any  dryer  in  those  sections  in  which  the  paper  maker 
wants  a  low  pressure. 

249.  Other  Steam-Circulating  Systems. — Various  means  of 
circulating  the  steam  in  the  dryer  part  have  been  patented  and 
installed.  Some  cause  the  high-pressure  steam  to  enter  one 
section,  pass  through  the  dryers  and  the  water  header  into  a 
second  section  of  dryers,  and  so  on,  if  desired,  into  a  third  section; 
this  method  maintains  a  rapid  circulation  of  steam  and  gives 
good  results.  The  idea  is  to  dry  the  paper  gradually,  by  having 
the  hotter,  high-pressure  steam  affect  the  hot,  nearly  dry  paper 
first.  Heating  the  paper  gradually  is  less  likely  to  produce 
blisters  and  cockling. 

250.  Special  Considerations. — The  paper  maker  must  re- 
member that  special  drying  systems  are  expensive  and  often 
troublesome,  if  not  carefully  installed  and  operated.  A  few  iron 
filings,  a  piece  of  a  washer,  or  a  piece  of  putty,  which  may  happen 
to  get  into  the  piping  or  into  a  valve,  will  cause  a  great  deal  of 
trouble,  and  will  be  hard  to  find  after  the  system  is  closed.  It 
should  be  a  rule  never  to  alter  a  dryer-pipe  installation  when  the 
machine  is  doing  well;  if  there  be  something  wrong,  try  to  ascer- 
tain^what  it  is  and  endeavor  to  devise  a  remedy.  If  the  dippers 
and^siphons  are  in  good  condition,  get  the  air  out  of  the  dryers 
by  means  of  pet  cocks  in  the  heads.     Put  a  steam  gauge  on  the 


162  PAPER-MAKING  MACHINES  §6 

steam  header  and  on  the  water  header ;  then,  if  the  water-header 
reading  is  equal  to  or  greater  than  the  steam-header  reading, 
change  the  gauges.  If  the  water-header  reading  still  shows 
high,  blank  off  the  part  that  is  getting  the  most  steam,  thus 
preventing  high  pressures  elsewhere  in  the  pipe. 

The  temperature  of  the  dryers  must  be  accurately  controlled 
and  maintained  uniform;  otherwise,  some  rolls  of  paper  will  be 
too  wet  and  some  too  dr3^  The  thinner  the  layer  of  air  between 
the  dryer  and  the  paper  the  better  is  the  dr3dng.  Excessive 
drying  is  also  a  source  of  breaks  on  the  dryers,  the  paper  winding 
around  a  dryer  and  often  necessitating  the  stopping  of  the 
machine  to  get  it  off. 

251.  Automatically  Controlling  the  Steam  Supply. — Nearly 
every  paper  machine  is  driven  by  a  steam  engine  or  a  steam 
turbine,  and  their  exhaust  steam  should  furnish  all  the  heat 
required  for  drying  the  paper  under  normal  conditions.  But 
papers  differing  in  quality  and  weight  require  different  amounts 
of  steam  in  drying.  There  are  three  general  methods  of  obtain- 
ing automatic  control  of  the  steam  supply;  they  are  based 
on  (a)  condition  of  the  paper,  (6)  pressure  in  the  dryer,  and  (c) 
temperature  in  the  dr3'er. 

By  method  (a),  a  light  roll,  on  free  arms,  rides  on  the  paper  as  it 
passes  from  one  drj'er  to  the  next;  it  is  situated  near  the  middle 
of  the  dryer  part,  and  one  of  the  arms  is  connected  to  an  appa- 
ratus for  operating  a  steam  valve,  so  as  to  admit  more  or  less  live 
steam  to  the  dryers.  If  the  paper  is  too  damp,  it  slackens,  the 
roll  fall^,  and  the  steam  valve  opens;  but  if  the  sheet  is  too  dry, 
this  operation  is  reversed.  When  once  adjusted  to  the  speed 
and  weight  of  the  paper,  this  device  works  well. 

Methods  (6)  and  (c)  are  similar  in  principle,  the  reason  for 
classifying  them  separately  being  that  a  pressure  gauge  does  not 
take  account  of  the  small  amount  of  superheat  that  the  steam 
sometimes  possesses.  The  steam  in  the  dryer  is  generally  in  a 
saturated  condition,  in  which  case,  the  pressure  gauge  gives  an 
accurate  measure  of  the  temperature  as  well  as  of  the  pressure. 
In  either  case,  the  result  is,  practically  speaking,  thermostatic 
control,  and  the  dryer  temperature  is  maintained  constant  when 
the  apparatus  is  set  for  particular  paper  conditions. 

252.  Steam  Traps. — Steam  is  one  of  the  most  valuable  com- 
modities used  in  the  mill;  and,  next  to  water,  it  is  the  most  easily 


§6  THE  DRYER  PART  163 

wasted.  A  large  amount  of  steam  is  required  for  drying  paper, 
and  the  profits  of  the  mill  may  depend  on  how  efficiently  it  is 
used.  To  prevent  steam  from  blowing  through  the  siphon  or 
dipper  and  still  permit  the  escape  of  the  condensation,  steam 
traps  are  used.  There  may  be  one  trap  to  each  dryer;  more 
frequentl}',  however,  there  is  one  trap  for  several  dryers,  or  even 
a  single  trap  for  all  the  dryers. 

The  purpose  of  the  steam  trap  is  to  hold  the  steam  in  the 
drj-ers  until  it  has  condensed  and  given  up  all  its  latent  heat. 
In  changing  from  a  pressure  of,  say,  10  pounds  per  square  inch, 
gauge,  to  0  pound  per  square  inch,  gauge  (atmospheric  pressure), 
a  pound  of  steam  gives  up  only  9.8  B.t.u.;  but  when  the  steam  at 
atmospheric  pressure  condenses  to  water  of  the  same  temperature 
and  pressure,  it  gives  up  970.4  B.t.u.,  or  nearly  100  times  as  much. 
Steam  at  10  pounds  pressure  is,  of  course,  hotter,  i.e.,  has  a  higher 
temperature,  than  at  atmospheric  pressure;  consequently,  in 
some  systems,  the  hot  steam  is  carried  as  steam  through  a  section 
of  the  diyer  part,  to  be  condensed  in  another  section,  that  next 
the  presses.  This  permits  the  passage  of  more  heat  at  a  lower 
temperature,  which  is  the  best  way  to  dry  paper. 

254.  Types  of  Steam  Traps. — There  are  two  general  types  of 
steam  traps — the  bell  type  and  the  tilting  type.  The  former 
consists  essentially  of  a  chamber,  in  which  hangs  a  bell  that  is 
constrained  to  move  vertically.  The  steam  and  the  condensate 
enter  under  the  bell.  Steam  escapes  under  the  bell,  which  rises 
as  the  water  gathers,  until,  at  a  certain  point,  a  water  discharge 
is  opened  and  the  steam-exhaust  supply  is  temporarily^  closed. 
The  water  is  forced  out,  and  the  bell  falls  until  it  operates  to 
close  the  water  discharge  opening,  the  steam  outlet  being  again 
opened.  An  air  vent  over  the  bell  lets  out  the  non-condensible 
gases.  The  hot  water  goes  back  to  the  boiler,  and  the  separated 
steam  is  generally  sent  to  one  or  more  dryers  at  the  wet  end, 
usually  through  a  common  header,  which  connects  all  the  traps. 

The  second  (tilting)  tj'pe  of  steam  trap  is  essentially^  a  two- 
pocket  cylinder,  mounted  at  the  middle  of  the  long  axis.  Steam 
and  water  enter  at  one  end,  the  steam  passing  baffles  and  escap- 
ing; the  water  accumulates  until  that  end  is  heavier  than  the 
other,  when  it  falls.  This  movement  shuts  off  the  steam  inlet 
and  outlet,  and  it  opens  the  water  outlet;  at  the  same  time,  the 
water  outlet  from  the  other  end  is  closed,  while  the  steam  inlet 
from  the  dryers  and  the  outlet  from  the  trap  are  opened.     In 


164  PAPER-MAKING  MACHINES  §6 

some  traps,  a  tilting  bucket  is  enclosed  in  the  vapor  chamber; 
it  is  operated  by  the  weight  of  water  condensed  in  the  bucket. 

In  some  systems,  a  vacuum  pump  removes  water  and  air  from 
the  traps.  The  pressure  in  the  trap  is,  of  course,  always  lower 
than  in  the  dryer. 

When  it  is  decided  to  use  valves  on  each  drj^er,  on  both  the 
steam  supply  and  the  water  discharge,  and  a  trap  is  used  on  each 
dryer,  then  the  valve  on  the  water  discharge  is  closed  only 
when  it  is  necessarj'^  to  repair  the  trap.  The  valve  on  the  steam 
supply  will  control  the  quantity  of  steam  to  the  drj^er.  Under 
these  circumstances,  a  good  siphon  performs  uniformly  as  long 
as  the  steam  pressure  is  uniform  and  the  paper  machine  is 
running  uniformly. 

Traps  are  always  liable  to  get  out  of  order;  and  if  there  are  too 
many,  some  are  always  out  of  commission.  It  pays  to  use  good 
traps. 

255.  Air  Pumps. — Methods  involving  forced  steam  circula- 
tion by  means  of  air  pumps  are  unexcelled,  when  they  receive 
constant  attention.  But  the  human  factor  in  the  problem  is  a 
large  one,  and  few  paper  mills  can  thus  afford  to  complicate  their 
paper-making  facilities. 

256.  Control  at  the  Press  End  of  Dryer  Part. — The  steam 
supply  to  the  press  end  of  the  dryer  part  should  be  capable  of 
easy  control  by  the  paper  maker.  A  valve  on  each  of  the  first 
few  dryers  will  enable  him  to  cut  the  supply,  if  the  surfaces  of 
the  dryers  become  hot  enough  to  spoil  the  paper;  and  such  a 
condition  will  soon  be  manifested  by  the  surfaces  of  the  dryers 
becoming  covered  with  fluff  or  filler. 

The  paper  at  the  calender  end  should  still  contain  8  %  or  9  % 
of  moisture,  because  paper  that  is  over-dried  is  spoiled.  In  all 
finer  grades  of  paper,  the  use  of  a  smoothing  press  before  the 
first  dryer,  when  the  paper  still  contains  at  least  60%  of  water, 
will  compress  the  fiber  into  the  surface  and,  at  the  same  time, 
compact  the  body  of  the  paper,  so  that  a  better  finish  can  be 
obtained. 


HANDLING  DRYER  FELTS 


257.  Importance  of  Controlling  Felt  Tension. — The  control 
of  the  tension  of  the  felts  is  a  most  important  feature  of  the 
management  of  dryers.     Efficient  and   uniform  drying  action 


§6  THE  DRYER  PART  165 

of  the  drj'cr  surfaces  can  be  obtained  only  by  securing  a  close 
and  uniform  contact  between  the  paper  and  the  dryers.  A  careful 
inspection  of  the  felt  tension  throughout  the  nest  will  often 
indicate  adverse  conditions,  either  because  the  felt  tightener  is 
badly  placed  or  because  it  does  not  have  sufficient  range  and 
promptness  of  action  as  a  felt  loosener.  A  dryer  felt,  if  made  of 
cotton,  will  shrink  violenth'  when  it  is  locally  wet,  and  it  will 
slacken  promptly  as  it  dries.  If  the  tighteners,  or  as  they  may 
trulj'  be  called,  loosening  devices,  are  not  so  placed  as  to  nullify 
the  evil  effects  of  this  shortening  and  lengthening  of  the  felt,  the 
life  of  the  felt  and  the  quantity  and  quality  of  the  output  will 
suffer. 

258.  Putting  on  a  New  Felt. — The  proper  method  for  putting 
on  a  new  felt  will  now  be  described.  First,  slack  up  on  the 
tighteners,  and  then  cut  the  old  felt  right  across  the  machine.  If 
there  is  no  old  felt  on  the  machine,  a  length  of  good  stout  twine, 
of  hemp  or  sisal,  must  be  threaded  through  the  dryers,  in  the 
middle,  following  exactly  the  path  of  the  felt  around  the  dryers, 
felt  rolls,  tighteners,  etc.  The  new  felt,  which  comes  in  a  roll, 
is  then  laid  down  across  the  machine,  between  the  last  dryer  and 
the  calenders,  or  the  size  press,  if  there  be  one.  The  end  is  cut 
square;  if  necessary,  ravellings  from  the  cut  part  are  used  for 
sewing  the  ends  together  later  on.  The  end  of  the  new  felt  is  then 
sewed  to  the  end  of  the  old  felt ;  or,  if  there  is  no  old  felt,  the  end  of 
the  new  felt  is  attached  to  the  end  of  the  threaded  twine.  The 
drj-ers  are  then  started  up.  If  the  lower  felt  is  being  replaced, 
the  new  felt  goes  down  under  the  dryers;  the  other  loose  end  of 
the  old  felt  is  taken,  as  it  comes  out,  and  is  passed  over  the  top  of 
the  calenders,  to  be  wrapped  around  a  reel  drum  and  wound  up. 
When  the  last  of  the  old  felt  comes  out,  the  end  of  the  new  felt 
is  detached  from  it,  and  is  sewed  tightly  to  the  other  end  of  the 
new  felt.  The  two  ends  of  the  felt  are  placed  together,  the  edges 
pointed  in,  and  the  seam  is  sewed  about  1  inch  in. 

The  seam  is  conveniently  made  b\'  tacking  the  loose  ends, 
joined  squarely,  to  a  board,  with  about  H  to  2  inches  extending. 
Following  a  thread,  a  straight  line  is  drawn  across  the  felt.  A 
long  ravelling,  as  long  as  can  be  handled  without  snarling,  is 
threaded  into  a  sailmaker's  needle,  and  the  two  ends  are  sewed 
together  on  the  mark.  A  good  stitch  is  to  put  the  needle  down 
about  I  inch  from  the  edge,  up  about  2  inches  along  the  line,  down 
again  through  the  first  hole,  up  through  a  new  hole  4  inches  from 


166  PAPER-MAKING  MACHINES  §6 

the  first,  down  again  through  the  second  hole,  and  so  on.  A 
quicker  method  is  to  pass  up  and  down  alternately,  every  2  inches 
or  so.  For  a  nice  job,  the  ends  should  be  inside  the  felt,  so  as  not 
to  mark  the  paper;  but  they  are  often  left  outside,  since  it  is 
then  much  easier  to  sew. 

A  top  felt  is  replaced  in  the  same  manner  as  that  just  described, 
except  that  the  old  felt  cannot  then  be  passed  so  conveniently^ 
over  the  calenders  and  wound  on  a  reel  drum.  In  this  case,  the 
old  felt  is  either  rolled  on  a  core  by  hand,  or  it  is  wound  up  on  the 
last  lower  drj^er  roll,  the  sweat  roll,  or  in  any  way  that  is  con- 
venient; frequently,  a  roll  is  started  on  a  core,  and  then  wound 
by  resting  it  on,  or  between,  dryers. 

259.  Strength  of  Felts. — Dryer  felts,  unlike  press  felts,  are 
usually  made  of  cotton  instead  of  wool,  and  are  sometimes  j  inch 
thick.  They  are  much  stronger  than  press  felts,  having  a  break- 
ing strength  of  300  pounds  per  inch  of  width;  the  breaking  strength 
of  the  average  press  felt  is  about  60  to  70  pounds  per  inch  of 
width,  though  a  fine- writing,  third-press  felt  of  a  tissue  machine 
ma}'  have  a  breaking  strength  sometimes  of  125  pounds  per  inch 
of  width. 

260.  Starting  the  Felts. — The  great  strength  of  a  cotton  dryer 
felt,  in  conjunction  with  its  decided  shrinkage  when  wet,  cause 
tremendous  strains  on  the  dryer  felts  and  rolls.  In  starting  up  a 
dryer  part  with  a  new  felt  or,  for  that  matter,  with  an  old  felt, 
start  the  dryers  free  of  paper;  run  slowly,  with  the  felt  stretchers 
slack  at  first,  watching  the  tighteners  and  guides,  to  see  that  all 
the  rolls  turn  and  that  the  felt  does  not  catch  anywhere. 

Turn  steam  into  the  dryers  for  about  20  minutes  before  starting 
up  and  look  to  see  that  the  dryers  are  empty  of  water.  If  a 
dryer  be  practically  half  full  of  cold  water,  it  will  act  as  a  sweat 
roll,  and  the  drj^er  edge  next  the  back  side  will  get  wet  from  the 
vapors  there ;  this  will  not  only  spoil  the  paper  but  may  also  result 
in  the  loss  of  a  dryer  felt.  When  run  cold,  dryers  are  Ukely  torust 
and  mark  fine  papers. 

261.  When  putting  on  a  dryer  felt,  it  may  tend  to  run  to  the 
front  side  or  back  side  of  the  machine,  notwithstanding  that  every 
precaution  has  been  taken  to  keep  the  run  of  felt  straight  and  to 
sew  the  seam  square  across.  In  correcting  this,  the  machine 
tender  should  bear  in  mind  the  simple  rule :  A  dryer  felt  will  run 
to  the  tight  side  when  tightened  at  the  side  at  which  it  leaves  the  dryer 


§6  THE  DRYER  PART  167 

cylinder;  and  it  will  run  to  the  slack  side  when  tightened  on  the  side 
that  is  going  to  the  cylinder. 

The  seam  should  always  be  squared  up  on  starting,  and  any 
tendencj^  to  run  ahead  on  either  side  can  be  corrected  by  making 
the  travel  of  that  side  longer;  if  this  be  not  done,  the  felt  will  be 
unevenly  stretched,  and  it  will  give  plenty  of  trouble  before  it  has 
been  in  service  very  long. 

When  shrinking,  a  dryer  felt  can  exert  a  pull  of  30  pounds  or 
more  per  inch  of  face  of  felt  rolls,  unless  the  stretch  roll  automatic- 
ally compensates  for  the  shrinkage.  This  puts  a  bending  moment 
on  a  felt  roll,  which  will  cause  it  to  sag  in  the  middle  until  the  felt 
becomes  too  loose  at  the  middle  and  too  tight  at  the  edges.  The 
result  is  that  the  paper  is  not  held  tightly  against  the  drj^ers  and 
remains  wet  in  the  middle;  and  when  the  local  felt-tension  con- 
ditions change,  a  break  is  almost  inevitable.  In  any  case,  a  good 
roll  at  the  winder  is  practically  impossible.  Cockling  troubles 
also  result  from  these  conditions,  because  minute  bubbles  of 
steam  make  small  blisters  in  the  paper,  and  lack  of  pressure 
imparts  a  sort  of  puckering  to  the  paper  as  it  dries. 

262.  Flapping. — Often  when  following  the  course  of  the  paper 
through  the  dryer  nest,  the  observer  will  perceive  a  continuous 
flapping  of  the  dryer  felts  at  certain  points.  This  flapping  is 
almost  invariably  caused  by  inaccurate  spacing  of  the  dryer 
gears,  or  in  some  imperfection  of  the  drive.  Many  old  machines 
have  been  speeded  up  in  order  to  increase  production,  and  the 
result  aimed  at  has  been  lost  because  of  continual  breaks  of  paper 
in  the  dryer  nest,  due  to  the  use  of  the  old-fashioned  cast  gears. 
The  remedy  is  always  to  order  cut  gears  when  the  paper  speed  is 
over  250  feet  per  minute.  By  watching  a  flapping  felt  and  count- 
ing the  flaps  per  revolution  of  a  dryer,  the  relationship  between 
the  drive  and  the  flap  will  be  perceived. 

Flapping  of  drj'-er  felts  may  also  be  caused  by  an  eccentric  dryer, 
one  that  does  not  rotate  about  its  axis;  it  may  likewise  be  caused 
by  a  warped  dryer.  To  ascertain  whether  or  not  a  dryer  is 
eccentric  or  is  warped,  hold  a  stationary  pointer  close  to  the 
revolving  dryer  surface;  if  the  revolving  surface  is  always  the 
same  distance  from  the  pointer,  the  dryer  is  turning  true,  but  if 
not,  it  is  eccentric  or  warped,  and  the  degree  of  eccentricity  can  be 
readily  noted. 

A  lack  of  symmetry  of  a  drying  cylinder,  due  either  to  eccen- 
tricity of  its  bearings  or  to  its  not  being  a  true  cylinder,  will 


168  PAPER-MAKING  MACHINES  §6 

produce  a  circumferentially  imperfect  movement  about  the  axis 
of  revolution,  which  causes  a  flapping  movement  of  the  paper  as 
it  journeys  from  one  dryer  to  another;  and  this  occurs  if  either  or 
both  of  two  successive  dryers  are  imperfect.  Flapping  is  some- 
times due  to  a  lack  of  proper  balance  between  the  speed  of  the 
paper,  the  diameter  of  the  dryers,  and  the  relative  position  of  the 
dryers. 

263.  Cause  of  Breaks. — It  is  well  to  note  here  that  a  dryer  that 
is  not  properly  machined,  so  that  the  foundry  skin  is  removed,  is 
liable,  if  not  well  "seasoned"  before  being  machined,  to  become 
misshapen  when  subjected  to  the  strains  caused  by  the  changes 
of  temperature  that  are  a  part  of  the  operation  of  paper  drying. 
Man}^  a  break  may  be  caused  by  the  stress  of  the  paper  resulting 
from  a  misshapen  dryer  or  an  eccentric  dryer  movement.  The 
distortion  of  the  dryer  movement  may  be  inherent  in  the  dryer 
itself,  or  it  may  be  due  to  unevenly  worn  bearings  or  to  imperfect 
gears.  Broke  may  be  the  result,  however  slight  the  non-uni- 
formity of  the  dryer  travel.  The  reason  that  the  paper  does  not 
break  oftener  when  flapping  occurs  is  because  of  the  natural 
elasticity  of  a  fabric  composed  of  cellulose  fibers. 

The  driving  side  of  a  nest  of  dryers  will  sometimes  exhibit  this 
phenomenon  when  it  is  not  evident  on  the  tending  side,  because 
the  bearings  on  the  driving  side  are  not  as  easily  lubricated ;  they 
may,  for  that  reason,  wear  more  rapidly,  thus  producing  a  rela- 
tively imperfect  mechanical  movement. 

264.  It  requires  time  to  evaporate  the  water  in  the  paper  and 
change  it  into  steam  on  the  dryer,  and  time  to  remove  the  vapor 
from  the  paper  as  it  travels  from  dryer  to  dryer.  Paper  shrinks 
as  it  dries,  and  it  stretches  as  it  becomes  damp,  and  if  the  air  it 
meets  is  moisture  laden,  the  paper  becomes  cooled  and  dampened 
between  dryers,  if  the  length  of  lead  is  too  great  for  the  speed  of 
the  paper;  such  a  condition  is  another  cause  for  flapping. 

265.  The  Spear  and  Its  Use. — When  paper  breaks  and  winds 
around  a  dryer,  it  must  be  cut  off  with  a  spear.  The  spear  is  a 
long,  light  pole,  with  a  sharp  steel  head  that  is  sometimes  slightly 
curved.  It  is  jabbed  under  the  edge  of  the  paper,  as  low  as 
possible  on  the  up-coming  side  of  the  dryer,  and  is  pushed  as  far 
as  possible;  but  it  is  withdrawn  when  the  cut  is  at  the  highest 
point,  as  the  dryer  turns.  A  new  jab  is  made  as  the  cut  again 
comes  up,  until  the  paper  is  cut  clear  across.     It  is  a  good  plan 


1 


§6  THE  DRYER  PART  169 

to  run  the  cut  part  over  to  the  next  dryer  and  along  the  lower 
tier.  On  a  fast  machine,  the  paper  is  immediately  broken  at  the 
press  or  wire,  and  the  dryers  are  slowed  down  or  stopped;  this  is 
quicker  in  the  end,  and  is  less  dangerous.  It  is  not  safe  to  stay 
near  the  man  who  is  using  the  spear. 


EVAPORATIVE  EFFECTS 

266.  Conditions  for  Maximum  Drying  Effects. — In  a  dryer 
nest,  the  diameter  of  the  dryers  being  as  large  as  possible,  the 
maximum  drying  or  evaporating  effect  per  dryer  should  be 
imparted  to  (i.e.,  as  much  water  should  be  evaporated  from) 
the  paper  as  can  be  taken  care  of  by  the  air  that  meets  the  paper 
between  the  dryers. 

Between  certain  limits,  it  is  evident  that  it  is  possible  to  obtain 
the  same  actual  and  relative  amounts  of  dryer  contact  and  air 
contact  for  the  paper  as  it  travels  on  its  way  through  the  dryers, 
whatever  be  the  diameter  of  the  dryers,  whether  48  inches  or  60 
inches;  these  limits  are  determined  by  the  width  of  the  machine, 
because  the  diameter  of  the  felt  rolls  must  increase  with  the  width, 
which  influences  the  spacing  of  the  drj^ers. 

267.  It  is  important  that  the  dryer  nest  be  so  designed  that  the 
paper  will  come  in  contact  with  a  dryer  before  the  felt  binds  it  to 
the  dryer;  and  it  is  important  that  the  felt  should  leave  the  paper 
before  the  paper  is  constrained  to  leave  the  dryer. 

In  considering  the  relative  position  of  dryers  and  the  distance 
between  the  paper  and  dryer  contacts,  it  must  be  remembered 
that  the  gears  are  all  of  the  same  diameter,  and  that  the  alternate 
upper  and  lower  gears  are  in  mesh;  there  must  be  clearance 
between  gears  on  contiguous  lower  dryers  and  contiguous  upper 
dryers,  and  this  rule  can  be  altered  only  by  the  use  of  idler  gears. 

268.  To  recapitulate :  in  order  to  obtain  the  maximum  output 
from  a  given  nest  of  dryers  under  normal  working  conditions, 
the  following  practical  conditions  must  be  met. 

(a)  The  drj-ers  must  be  perfect  cylinders,  revolving  on  true 
mechanical  journals,  whose  axes  should  coincide  with  the  theo- 
retical axes;  the  gears  must  be  accurately  cut  and  accurately 
connected  with  the  dryers. 

(6)  The  length  of  contact  of  the  paper  with  each  dryer  and 
with  the  air  between  the  dryers  must  be  adjusted  to  prevent 
flapping. 


170  PAPER-MAKING  MACHINES  §6 

(c)  The  paper  must  meet  each  dryer  before  the  felt,  and  must 
leave  the  dryer  after  the  felt,  every  time. 

269.  Ventilation. — Good  results  cannot  be  obtained  from  the 
dryer  nest  unless  the  ventilation  conditions  are  such  that  an 
ample  supply  of  moderately  dry  air  is  constantly  rising  around 
the  dryer  nest.  From  2  to  3  tons  of  water  must  be  carried  away 
by  the  air  for  each  ton  of  paper  made;  and  if  the  air  supply  is  not 
ample,  good  drying  conditions  are  not  possible.  A  homely 
comparison  that  may  serve  to  impress  the  idea  on  the  reader's 
mind  is :  a  washerwoman  prefers  a  windy  day  to  dry  the  clothes, 
even  when  the  sun  is  not  shining,  to  a  sunshiny  day  when  there 
is  no  air  stirring;  but  the  best  day  is  when  there  is  a  warm,  dry 
breeze. 

270.  Amount  of  Water  Evaporated  by  Dryers. — The  amount 
of  water  that  the  dryers  evaporate  per  day  is  easily  found  when 
certain  quantities  are  known  or  specified.     Thus,  let 

N  =  total  weight  of  paper  delivered  by  the  dryers  per  day 

of  24  hours; 
n  =  average  per  cent  of  water  in  N  (expressed  decimally); 
M  =  weight  of  bone-dry  material  in  the  paper  delivered; 
m  =  weight  of  water  in  iV  ( =  n  X  A^) ; 
e  =  weight  of  water  evaporated  by  dryer  nest; 
w  =  weight  of  water  in  paper  entering  dryers; 
W  =  total  weight  of  paper  and  water  entering  dryers; 
p  =  per  cent  of  bone-dry  material  in  W  (expressed  decimally) . 

All  weights,  must  be  expressed  in  the  same  unit,  say  the  ton  of 
2000  pounds. 


Then, 

W  = 

M  ■\-  w 

=  M  +  7n  +  e  =  M-{-  nN  -{-  e; 

(1) 

from  which, 

M  =  W-W  =  W-m-e. 

(2) 

Further, 

M  =  vW; 

(3) 

p' 

(4) 

and 

M  =  N{1  -  n). 

(5) 

Also, 

N  =  M  ■]-m; 

(6) 

1  —  n  ' 

(7) 

M      A(l-n) 
~  V  ~         V 

(8) 

and 

e  =  W  -  N. 

(9) 

§6  THE  DRYER  PART  171 

These  formulas  are  very  simple,  and  they  are  all  self  evident. 
The  following  example  will  show  the  application  of  several  of 
them.  The  per  cent  of  water  in  the  finished  paper  (denoted 
above  by  n)  varies  considerably;  it  usually  amounts  to  6%  to  9%, 
though  10%  is  considered  as  commercially  dry  paper.  The 
per  cent  of  dry  material  entering  the  dryer  part  (denoted  above 
by  p)  is  determined  by  actual  test  in  each  case. 

Example. — A  machine  has  a  total  output  of  25  tons  of  paper  per  day  of 
24  hours,  and  the  paper  contains  10%  of  water.  It  is  found  by  test  that 
38%  of  the  mixture  entering  the  dryers  is  bone-dry  material,  (a)  What  is 
the  total  weight  of  paper  and  water  entering  the  dryers  per  day?  (b)  What 
is  the  total  weight  of  water  evaporated  per  day  by  the  dryers? 

Solution. — (o)  Here  A''  =  25  tons,  n  =  .10,  p  =  .38,  and  it  is  desired 
to  find  W,  the  total  weight  of  water  and  paper  entering  the  dryers.  The 
given  quantities  are  N,  n,  and  p,  and  W  is  to  be  found.  These  quantities, 
and  only  these  are  contained  in  formula  (8);  hence,  using  this  formula, 

_       iV(l  -  n)       25(1  -  .10)        „^ 

W  = = =  60  tons,  very  nearly.     Ans. 

p  .38 

(b)  By  formula  (9), 

e  =  TF  -  A^  =  60  -  25  =  35  tons.     Ans. 


271.  Number  of  Dryers  Required. — A  rough  approximation 
to  the  capacity  of  the  drj^er  part  may  be  arrived  at  as  follows: 
If  the  paper  being  made  is  newsprint  or  its  equivalent  in  furnish 
and  weight,  allow  one  48-inch  dryer  for  every  20  feet  per  minute 
of  paper  speed ;  or,  for  a  60-inch  dryer,  allow  one  dryer  for  every 
25  feet  per  minute  of  paper  speed.  Thus,  if  the  paper  speed  be 
600  feet  per  minute,  there  should  be  600  -^  20  =  3048-inch  dryers 
or  600  -^  25  =  24  60-inch  dryers.  For  book  and  writing  papers, 
allow  one  48-inch_dryer  for  every  10  feet,  per  minute  of  paper 
speed. 

The  following  table  represents  actual  practice ;  it  checks  quite 
closely  the  rough  rule  just  given: 


172 


PAPER-MAKING  MACHINES 


§6 


Book  and  Writing  Papers 

No.  of  dryers.     Diam. 

Maximum  speed 

(inches) 

of  paper,  feet  per 

minute 

1 
1 

48 

60 

72 

250 

24 

20 

17 

325 

30 

26 

22 

400 

36 

32 

27 

450 

42 

36 

30 

500 

48 

40 

37 

Newspaper 


300 

15 

12 

10 

375 

18 

15 

13 

450 

22 

18 

15 

525 

26 

21 

18 

600 

30 

24 

20 

1100 

40 

272.  Calculating  Dryer  Surface  Required. — The  following 
empirical  formula  may  be  used  for  calculating  the  amount  of 
dryer  surface  required  for  various  kinds  of  papers.  In  this 
formula, 

S  =  speed  of  paper  in  feet  per  minute; 

L  =  peripheral   length    (in  feet)    of   dryers   in   contact   with 

paper  when  in  operation; 
t  =  temperature  of  steam  at  pressure  carried  in  degrees  Fah. ; 
d  =  thickness  of  dryer  shell  in  inches; 
w  =  weight  of  paper  in  500  sheets,  24"  X  36". 

Then, 

2.7L{t  -  212) 


and 


S  = 


L  = 


wd 


Swd 


2.7  (t  -  212) 


(1) 


(2) 


Example  1. — Suppose  it  is  desired  to  make  30-pound  newsprint  at  a  rate 
of  600  ft.  per  min.;  how  many  dryers  having  a  thickness  of  |  in.  are  required 
when  the  steam  pressure  is  10  lb.  per  sq.  in.,  gauge? 


§6  THE  DRYER  PART  173 

Solution. — Referring  to  the  steam  tahle  at  the  end  of  Vol.  Ill,  the  tem- 
perature of  the  steam  at  10  lb.,  gauge,  is  239.4°.  Neglecting  the  fraction, 
the  value  of  I  is  239.     Substituting  in  formula  (2)  the  values  given, 

^   _  600  X  30  X  .75  _  . 

^  -2.7(239-212)  "  ^^^  "" 
The  value  of  L  just  found  is  the  length  of  the  periphery  of  dryer  shell 
that  is  in  contact  with  the  paper.  But,  since  a  little  less  than  one-half  of 
the  periphery  of  any  dryer  is  in  contact  with  the  paper  (see  Art.  226),  the 
periphery  of  a  single  dryer  must  be  greater  than  185  X  2  =  370  ft.,  which 
is  far  too  great  for  any  dryer.     The  periphery  of  a  48-inch  cylinder  is 

^^  ^12^^^^  =  12.5664  ft.,  and  one-half  of  this  is  6.2832  ft.  Assuming 
that  the  length  of  the  arc  of  contact  between  the  paper  and  the  dryer  is 
6  ft.,  the  number  of  48-inch  dryers  required  is  185  -r-  6  =  31.     Ans. 

Example  2. — How  many  feet  of  peripheral  contact  on  dryers  is  required 
for  18-pound  tissue  at  150  ft.  per  min.,  the  thickness  of  the  dryer  shell  being 
1§  in.,  and  the  steam  pressure  75  lb.  per  sq.  in.,  gauge?  How  many  60-inch 
dryers  would  be  required? 

Solution. — Referring  to  the  steam  table  at  the  end  of  Vol.  Ill,  the  tem- 
perature of  the  steam  is  321°  very  nearly.  Substituting  in  formula  (2)  the 
values  given,  the  total  length  of  the  peripheral  contact  is 

-.        150  X  18  X  1.5       ,o7ftfx       A 
^  =   2.7(321  -  212)  =  1^-^^  ^^-     ^^'- 

In  example  1,  it  was  found  that  the  arc  of  contact  for  a  48-inch  dryer 
might  be  taken  as  6  ft.;  for  a  60-inch  dryer,  it  may  therefore  be  taken  as 

6  X  2o  =  7.5  ft.     Consequently,  the  number  of  60-inch  drj^ers  is  13.76 

-^  7.5  =  1.83 +,  or  2  dryers.     Ans. 

273.  Calculating  the  Air  Supply. — The  water  that  is  evaporated 

by  the  dryers  is  carried  away  by  air,  which  is  supplied  and  taken 

away  by  some  mechanical  means.     A  given  quantity  of  air,  say 

a  cubic  foot,  will  absorb  a  certain  amount  of  moisture  (water); 

and  if  the  air  be  dry  and  warm,  it  will  absorb  much  more  moisture 

than  cold,  damp  air.     Under  the  usual  working  conditions,  it 

takes  about  40  pounds,  which  is  equivalent  to  about  500  cubic 

feet,  to  carry  away  1  pound  of  water.     Referring  to  the  example 

of  Art.  270,  the  weight  of  water  evaporated  by  the  dryers  in  24 

35  X  2000 
hours  was  found  to  be  35  tons,  which  is  equivalent  to    04  ^  fiO 

=  48.6,  say  50  pounds  of  water  per  minute.  Consequently,  to 
dispose  of  this  water,  air  must  be  supplied  to  the  dryers  and  con- 
ducted away  from  them  at  the  rate  of  about  50  X  500  =  25,000 
cubic  feet  per  minute;  and  this  is  the  amount  necessary  to  furnish 
when  making  25  tons  of  paper  per  day  under  the  conditions 
specified. 


174  PAPER-MAKING  MACHINES  §6 

274.  Supplying  the  Air. — The  air  may  be  supplied  by  a  fan  that 
is  situated  in  the  basement.  The  fan  blows  the  air  through  an 
air  duct,  which  has  upright  outlets  at  intervals,  and  which  dis- 
charges the  air  into  the  dryer  nest.  This  method  is  direct  and 
efficient;  and  if  the  system  be  well  designed,  it  will  increase  the 
output  of  the  machine  in  both  quantity  and  quality. 

Placing  steam  pipes  either  below  the  dryer  nest  or  above  it, 
will  induce  a  strong  current  of  up-going  air;  but  by  placing  the 
steam  pipes  below  the  dryer,  the  air  is  warm  when  it  reaches  the 
dryers,  and  warm  air  will  absorb  more  water  than  cold  air.  If 
the  steam  pipes  are  placed  above  the  dryer,  they  will  induce  a 
current  of  colder  air  through  the  nest  than  if  they  were  placed 
below  the  drj'-ers;  but  when  in  this  latter  position,  they  have  the 
advantage  of  keeping  the  air  from  getting  chilled  b}^  cold  drafts 
from  the  windows  or  the  cupola  in  the  room,  or  by  conduction 
through  a  poorly  insulated  roof,  which  will  force  the  air,  if  chilled 
to  the  dew-point,  to  drop  its  water  on  the  top  felts  in  the  form  of 
dew  or  light  rain. 

The  air  leaving  the  dryers  carries  with  it,  in  the  form  of  water 
vapor  and  sensible  heat,  the  equivalent  of  most  of  the  heat 
abstracted  from  the  steam  in  the  dryers.  A  recently  patented 
system  recovers  much  of  this  heat  by  warming  the  incoming  air. 

275.  Humidity. — There  are  three  principal  factors  concerned 
in  the  removal  of  the  water  evaporated  by  the  dryers:  (a)  the 
volume  of  air  passing  through  the  dryer  part  relative  to  the 
amount  of  water  to  be  evaporated;  (6)  the  temperature  of 
the  air;  (c)  the  humidity  of  the  air.  A  cubic  foot  of  dry  air  at  any 
particular  temperature  will  hold  a  certain  definite  amount  of 
water,  the  exact  amount  depending  on  the  temperature  of  the 
air.  When  the  air  has  taken  up  all  the  water  it  can  hold,  it  is 
said  to  be  saturated.  If  saturated  air  be  cooled,  it  will  deposit 
some  of  its  moisture  in  the  form  of  dew  or  rain;  but  if  it  be  heated, 
it  can  then  absorb  more  moisture.  Saturated  air  is  also  said  to 
have  a  humidity  of  100%;  and  air  containing  less  moisture  than 
that  required  to  saturate  it,  will  have  a  humidity  ranging  from 
0%,  when  it  is  perfectly  dry  and  moisture  free,  to  100%,  when  it 
is  saturated.  The  less  saturated  it  is  the  more  moisture  it  can 
absorb,  and  the  more  it  can  be  cooled  before  reaching  the  dew 
point,  which  is  the  temperature  at  which  precipitation  or  con- 
densation occurs,  i.e.,  the  temperature  at  which  the  humidity  is 
100%.     The  student  is  advised  to  re-read  Arts.  129  and  130  of 


§6  THE  DRYER  PART  175 

Elements  of  Physics,  Part  2,  in  Vol.  I,  and  to  refer  to  the  use  of 
the  hygrometric  chart  in  Vol.  V,  under  Paper  Testing. 

276.  Removing  the  Air. — Referring  back  to  Fig.  65,  the  illus- 
tration shows  a  design  of  a  hood  H  over  a  dryer  nest,  with  one  or 
more  stack  openings  V  on  top.  Each  stack  is  provided  at  its 
outlet  with  a  fan  for  drawing  the  moisture-laden  air  from  the 
dryer  nest  and  discharging  it  out  of  doors.  In  some  mills,  a  tall 
stack,  with  natural  draft,  is  preferred  to  the  fan.  Since  the 
arrangement  of  drj^er  hood,  fans,  and  stacks  here  shown  will  tend 
to  draw  the  air  from  the  machine  room  more  easily  than  from  the 
inside  of  the  dryer  nest  and  from  under  the  dryer  felts,  and  since 
the  air  from  the  back,  or  driving,  side  is  generally  more  moisture 
laden  than  on  the  front  side,  it  is  a  good  plan  to  have  the  hood 
overhang  more  on  the  driving  side  and  to  turn  it  toward  the 
drj^ers,  so  as  to  induce  the  air  to  come  from  under  the  felt 
and  into  the  hood.  If  moist  air  be  not  removed  before  it 
cools,  the  moisture  is  condensed  out  when  the  air  strikes  a 
cold  surface,  and  falls  like  rain  from  a  cloud.  It  will  therefore 
be  seen  that  the  design  and  construction  of  the  roof  is  of  con- 
siderable importance.  In  some  cases  when  fans  are  in  use,  the 
stacks  may  discharge  through  openings  in  the  walls  instead  of 
through  the  roofs. 

277.  Roofs. — A  high  roof,  with  a  large-size  cupola,  is  a  good  aid 
to  paper  drying.  The  roof  should  be  of  an  anti-sweat  design, 
preferably  with  an  air  space  between  the  roof  proper  and  a 
false  roof  that  is  composed  of  paper,  asbestos,  or  composite 
boarding,  which  is  supported  by  the  main-roof  trusses.  The 
cupola  should  be  high  enough  to  allow  of  ample  window  spacing, 
which  should  run  from  end  to  end  of  the  cupola;  and  the  lower 
sashes  should  be  so  arranged  as  to  afford  an  easy  way  out  for  the 
moisture-laden  air  of  the  machine  room,  but  still  keeping  the  rain 
from  beating  down  in  case  of  a  storm. 

The  accumulation  of  moist  air  under  a  wooden  roof  induces 
decay;  untreated  timbers  seldom  remain  in  good  condition  for 
more  than  seven  years.  The  proper  construction  of  roofs  has 
received  considerable  attention  and  study  in  recent  years.  The 
reader  is  referred  to  articles  on  this  subject  by  R.  J.  Blair,  in  Pulp 
and  Paper  Magazine  of  Canada  for  Jan.  1  and  8,  1920;  in  Paper, 
Vol.  25,  pp.  819-827  (1919);  and  by  H.  S.  Taylor,  in  Pulp  and 
Paper  Magazine  of  Canada  for  July  8, 1920. 


176  PAPER-MAKING  MACHINES  §6 

278.  The  Size  Press. — An  important  part  of  many  paper 
machines  that  make  writing  papers  is  the  size  press.  As  the  paper 
comes  from  the  last  dryer,  it  is  usiiall}'  cut  into  strips  by  a  set  of 
slitters,  similar  in  design  to  those  described  in  Art.  303,  Part  4 
of  this  section,  and  which  are  mounted  on  the  end  of  the  drj'^er 
frame.  The  strips,  cut  in  accordance  with  the  size  of  the  sheets 
desired,  are  passed  under  a  paper  roll  to  submerge  the  paper  in 
the  size  solution,  then  under  and  back  through  the  nip  between 
the  lower  and  upper  size-press  rolls;  they  are  then  led  to  a  cutter 
and  layboy  (see  Tub  Sizing  and  Finishing,  Vol.  V),  if  loft  dried,  or 
over  a  short  dryer  nest,  of  5  or  6  dryers,  if  sized  in  full  width. 
Machines  are  now  equipped  with  slat  or  festoon  dryers,  to  pro- 
duce an  accelerated  air  drying;  these  machines  are  described  in 
Section  3,  Vol.  V. 

In  the  case  of  thin  papers,  it  is  customary  to  wind  the  sized 
paper  on  reels  and  cut  it  later  for  loft  drying;  it  may  even  be  sized 
in  an  operation  that  is  subsequent  to  the  making  of  it. 


PAPER-MAKING 
MACHINES 

(PART  3) 


EXAMINATION  QUESTIONS 

(1)  (a)  What  is  meant  by  the  dryer  section?  (6)  What  por- 
tion of  the  removal  of  water  from  the  paper  takes  place  here? 

(2)  (a)  Explain  the  function  of  the  smoothing  rolls?  (6) 
Where  are  they  located  and  why? 

(3)  Why  is  a  felt  used  on  the  dryers,  and  of  what  is  it  made? 

(4)  Does  a  dryer  felt  stretch  or  shrink  when  wet? 

(5)  Explain  the  contrivance  by  which  any  change  in  the 
length  of  a  felt  is  taken  care  of  automatically. 

(6)  Why  should  air  and  why  should  water  be  removed  from 
dryers? 

(7)  Describe  two  methods  for  removing  water? 

(8)  Explain  the  presence  of  water  in  the  dryer. 

(9)  Suppose  1  lb.  steam  is  put  into  one  dryer  at  10  lb.  gauge 
pressure  and  removed  as  steam  at  0  lb.  gage,  and  1  lb.  into  a 
second  dryer  at  0  lb.  and  removed  as  water  at  the  same  tem- 
perature; which  will  dry  more  paper? 

(10)  What  is  the  principle  of  the  guiding  of  felts? 

(11)  (a)  What  is  the  function  of  the  steam  joint?  (6)  What 
precautions  should  be  taken  with  it? 

(12)  What  means  may  be  used  to  maintain  a  uniform  tem- 
perature in  the  dryers? 

(13)  What  is  a  steam  trap  for,  and  how  does  it  work? 

(14)  Explain  how  a  new  dryer  felt  is  put  on. 

(15)  Mention  some  causes  of  flapping  of  the  paper  on  the 
machine. 

(16)  What  factors  influence  the  rate  of  drj-ing  of  paper? 
§6  177 


178  PAPER-MAKING  MACHINES  §6 

(17)  If  a  machine  were  to  make  55  tons  of  paper  containing 
8%  moisture  in  24  hours  and  the  paper  contained  30%  bone-dry 
paper  on  entering  the  dryers,  how  much  water  would  be  removed 
in  drying? 

(18)  What  is  meant  by  (a)  dew-point?  (6)  humidity?  (c) 
siphon?  (d)  felt  dryer?  (e)  dancing  roll? 


SECTION  6 

PAPER-MAKING 
MACHINES 


(PART  4) 


CALENDERS,  SLITTERS  AND  WINDERS 


THE  CALENDER  END 


DESCRIPTION  OF  CALENDERS 

279.  The  Spring  Roll.— At  the  calender  end  of  the  dryer  part, 
the  paper  passes  under  a  spring  roll  N,  Fig.  64,  before  entering  the 
nip  of  the  calender.  This  is  a  paper  roll,  which  is  supported  in. 
spring  bearings,  one  of  which_is  shown  in  detail  in  Fig.  72. 
Referring  to  Fig.  72,  the 
bearing  proper  5  is  a  float- 
ing or  moving  bearing,  en- 
tirely supported  by  springs, 
one  of  which  S  is  shown  in 
detail ;  it  is  kept  in  position 
and  adjustment  by  the  bolt 
J.  When  the  paper  tension 
varies,  as  the  paper  is  pulled 
from  the  dryers  by  the 
calenders,  this  spring  roll 
(under  which  the  paper 
passes)  can  rise  or  fall  in  its  bearing  because  of  the  action  of  the 
springs;  and  this  compensates  for  temporary  variations  of  the 
tension. 
§6  179 


Fig.   72. 


180 


PAPER-MAKING  MACHINES 


§6 


280.  The  Calender  Stack. — Fig.  73  shows  a  9-roll  stack  of 
calenders,  and  a  similar  roll  is  shown  in  Fig.  74.  The  paper,  as 
it  is  passed  from  the  dryers,  is  brought  over  the  top  roll  and  enters 


t=^ 


Fig.  73. 


between  the  top  roll  A,  Fig.  73,  and  the  roll  B,  next  below  it. 
The  paper  is  guided  by  bent  steel  fingers,  or  ductors,  into  each 
succeeding  nip.     On  coming  out  from  the  first  nip,  the  paper  is 


§6  CALENDERS,  SLITTERS  AND  WINDERS         181 

guided  back  into  the  next  lower  nip,  proceeding  in  this  way  from 
nip  to  nip  until  it  finally  comes  out  on  top  of  the  bottom  roll, 
on  the  side  away  from  the  drj^ers  and  toward  the  reel.  In  the 
stack  here  shown,  the  top  roll  turns  away  from  the  dryers,  and  the 
paper  is  carried  over  and  fed  from  behind;  consequently,  if  there 
were  an  even  number  of  rolls  (saj'^  8  or  10),  the  paper  would  not 
pass.  With  an  odd  number  of  rolls,  an  extra  roll,  called  a  pinch 
roll,  over  the  top  roll,  is  sometimes  placed  at  the  top  of  the  stack, 
to  help  in  bringing  the  paper  over;  or  the  paper  may  be  passed 
directly  to  the  first  nip. 

The  steel  doctor  blades  D  scrape  off  the  paper  as  it  comes  from 
each  nip,  and  thus  keep  it  from  traveling  up  the  rolls.  The 
ductors  are  on  the  in-running  side  of  the  upper  roll  of  each  pair 
of  rolls;  and  there  are  usually  5  or  6  ductors  on  the  tending  side 
of  the  machine,  to  handle  the  "tail."  The  doctors  are  always 
on  the  out-running  side  of  the  roll.  The  ductors  lead  the  paper  to 
the  nips;  the  doctors  lead  the  paper  away  from  the  rolls.  (See 
Part  3,  Art.  223.) 

A  popular  type  of  calender  doctor  has  a  universal  control,  by 
means  of  which,  all  the  doctors  are  connected  together,  and  all  are 
thrown  against  or  away  from  the  rolls;  but  individual  doctors 
can  be  operated  independently,  if  necessary.  Each  doctor  has  a 
flexible  blade  of  soft  metal,  so  the  chilled-iron  calender  rolls  will 
not  be  injured  by  contact  with  it;  and  the  doctors  are  all  held 
against  the  rolls  with  a  uniform,  relatively  light,  pressure  by 
springs,  the  tension  of  which  (and  the  corresponding  pressure  of 
the  doctors)  is  adjustable.  All  the  doctors  are  operated  from  the 
front  side  of  the  machine. 

The  back  tender  throws  the  end  of  the  paper  into  the  entering 
nip,  and  it  automatically  feeds  through  the  calenders  until  it  is 
scraped  off  the  reel  side  of  the  bottom  roll;  it  is  then  carried  by  the 
back  tender  and  wrapped  around  a  reel  C34inder.  On  machines 
that  are  not  equipped  with  doctors  and  ductors,  the  calender 
stack  is  a  prolific  source  of  accidents,  because  of  the  tendency  to 
use  the  fingers  to  feed  the  paper  through  the  nips.  The  safe 
way  is  to  draw  the  loose  end  down  tight  with  one  hand,  and  then 
push  the  sheet  into  the  nip  with  the  closed  fist  of  the  other  hand. 
A  good  machine  man  is  Always  Careful  Everywhere. 

281.  Purpose  of  the  Calenders. — The  purpose  of  the  calender 
stack  is  to  compact  the  paper  and  give  it  a  fine,  smooth  finish; 
this  effect  is  achieved  on  both  sides  of  the  paper  by  the  friction 


182  PAPER-MAKING  MACHINES  §6 

and  pressure  of  the  rolls  between  which  the  paper  passes.  The 
lowest  roll  of  the  stack  is  driven  mechanically,  and  this,  in  turn, 
drives  those  above  it  by  friction.  There  is  a  certain  amount  of 
slip  between  these  rolls,  and  the  result  is  that  an  enormous 
aggregate  of  friction  acts  on  the  paper  as  it  passes  through. 

In  order  to  give  a  fine  finish,  the  calender  rolls  are  made  of  a 
fine-grained  cast  iron  that  is  susceptible  of  a  high  polish;  it  is 
important  that  these  rolls  be  made  of  chilled  iron.  Since  a  soft 
paper  is  more  easily  smoothed  than  a  hard  paper,  the  surface  of 
the  paper  is  sometimes  dampened  (as  for  water  finish)  with  a 
fine  water  spray  or  a  steam  jet,  which  is  played  on  its  surface  as 
the  paper  enters  the  nip  of  the  calenders.  If  the  paper  is  made 
too  wet,  the  friction  of  the  calenders  may  develop  black  spots 
on  the  sheets;  also,  softening  the  paper  at  this  point  may  reduce 
the  size  fastness  of  the  paper. 

282.  Use  of  Sweat  Roll  and  Smoothing  Roll. — Sometimes  the 
paper  is  moistened  on  the  surfaces  by  passing  over  a  sweat  roll. 
This  is  a  small  roll,  like  a  dryer,  but  filled  with  cold  water  to 
condense  moisture  from  the  air  on  the  paper,  which  will  soften 
the  paper  and  assist  the  work  of  the  calenders.  Moistening  the 
paper  with  the  intention  of  obtaining  a  fine  glaze  finish  is  a 
procedure  also  carried  on  in  the  finishing  room  on  the  super- 
calenders. 

The  use  of  smoothing  rolls  before  the  dryer  nest,  as  shown  in 
Fig.  64,  smooths  the  surface  of  the  paper  while  it  is  still  very 
moist,  and  is  therefore  soft  and  pliable;  they  squeeze  down  the 
surface  to  a  finish  with  much  less  pressure  than  the  calenders 
must  exert  to  get  the  same  result,  and  should  leave  more  strength 
in  the  paper,  with  no  ill  effect  on  the  sizing. 

283.  Moisture  in  Paper  at  Calenders. — The  paper  should  go 
to  the  calenders  containing  close  to  10%  of  water;  if  it  contain 
much  less,  it  has  a  dry,  brittle  feel,  is  liable  to  break,  and,  being 
hard,  does  not  iron  out  easily.  When  paper  is  coming  through 
in  this  condition,  the  steam  supply  to  the  dryer  nest  must  be 
reduced  until  the  moisture  content  of  the  paper  is  normal. 

284.  Calender  Doctors. — When  selecting  calender  doctors, 
make  sure  that  they  fulfill  the  following  conditions:  first,  they 
must  be  capable  of  quick  adjustment  to,  and  release  from,  the 
surface  of  the  rolls;  second,  they  must  be  capable  of  exerting  a 
fair  pressure  on  the  rolls ;  third,  the  blades  must  be  flexible  enough 


§6  CALENDERS,  SLITTERS  AND  WINDERS         183 

to  shape  themselves  to  conform  to  the  surface  of  the  roll  by 
means  of  the  adjusting  screws. 

The  steel  blade  ductors  should  lead  the  paper  easily  to  the 
nips,  so  as  to  preclude  any  necessity  for  any  one  of  the  machine 
crew  getting  his  fingers  in  such  a  position  as  to  be  drawn  between 
the  rolls. 


CALENDER  TROUBLES 

285.  Hard  and  Soft  Spots. — As  the  paper  is  passed  over  the 
reel  and  is  reeled  into  rolls,  any  inequalities  in  bulk  will  show 
quickly.  Bulk  is  a  term  that  expresses  the  thickness  of  paper  as 
compared  with  its  weight;  a  paper  that  is  thick  for  its  weight  is 
said  to  bulk  well.  If  a  paper  bulks  unevenly  across  the  machine, 
it  will  (if  it  does  not  break  at  the  calenders)  wrap  unevenly 
around  the  reel  cylinders,  making  what  the  machine  tender  calls 
hard  and  soft  spots  in  the  roll.  The  hard  places  have  the  best 
bulked  paper,  because  the  thickness  of  the  paper  makes  it  reel 
tighter  than  the  paper  that  has  a  poorer  bulk  and  cannot,  there- 
fore, fill  the  same  space  as  the  reel  roll  grows;  this  causes  soft- 
feeling,  loose  places  in  the  roll.  The  back  tender  is  very  prone 
to  correct  the  inequalities  of  bulking,  causing  soft  spots  in  the 
reel,  by  trying  to  remedy  the  faults  at  the  calenders.  This  can 
be  done,  and  sometimes  must  be  done,  by  altering  the  diameter 
of  the  calender  rolls  by  changing  their  temperature.  The 
place  where  the  roll  is  hard  indicates  the  part  of  the  calender 
rolls  that  can  thus  be  heated  by  friction  or  by  steam.  Opposite 
the  soft  places  on  the  reel,  which  show  that  the  paper  is  thinner 
there  or  does  not  bulk  well,  cold  air  is  blown  by  air  pipes  from  a 
blower  onto  the  calender.  This  tends  to  reduce  the  diameter 
of  the  rolls  at  these  points,  which  reduces  the  relative  pressure 
at  the  same  points,  the  result  being  that  the  paper  is  not  calen- 
dered so  severely  where  the  soft  spots  indicate  lack  of  bulk. 

286.  Correcting  for  Uneven  Bulking. — In  order  to  maintain 
the  test  strength  of  the  paper,  it  is  better  to  correct  first  for 
uneven  bulking  through  the  machine.  The  slices  are  the  first 
sources  of  trouble;  see  that  they  are  of  uniform  height  from  the 
wire  clear  across  the  machine.  The  drier  the  paper  is  as  it  leaves 
the  press  rolls  the  better  it  will  bulk;  so  look  to  the  press  rolls 
for  uniform  pressure  and  accurate  crowning,  to  correct  bulking 
troubles.     An    even    drying    across   the   machine    is   essential; 


184  PAPER-MAKING  MACHINES  §6 

look  out  for  felts  that  arc  damp  in  the  center  and  for  places 
where  steam  collects.  Every  paper  machine  has  its  own  charac- 
teristic troubles  and  faults,  and  every  part  of  the  machine 
should  be  examined  thoroughly  when  there  is  trouble  in  bulking. 
Uneven  bulking  can  always  be  corrected  if  the  causes  are  located ; 
the  difficulty  is  to  find  them.  The  trouble  may  be  in  incorrect 
grinding  of  the  rolls;  regrinding  is  the  cure  for  this. 

The  machine  tender  should  keep  it  always  in  mind  that  two 
wrongs  do  not  make  a  right;  hence,  if  the  paper  is  unevenly 
bulked  (is  not  of  uniform  thickness  on  the  roll)  when  it  enters 
the  calenders,  and  if  the  calenders  are  truly  ground  and  the 
bottom  roll  is  properly  crowned,  then  the  calenders  is  not  the 
place  to  correct  for  uneven  bulking.  A  machine  tender  must, 
of  course,  keep  the  paper  going,  and  the  quickest  way  to  correct 
a  fault  is  temporarily  the  best  w^ay;  at  the  same  time,  a  little 
careful  thinking  may  suggest  a  better  remedy,  one  that  can  be 
tried  at  the  end  of  the  week,  when  the  machine  is  shut  down. 

287.  Causes  of  Some  Calender  Troubles. — The  following  are 
some  of  the  causes  of  trouble  at  the  calenders:  Too  little  crown 
on  the  press  rolls  will  cause  soft  spots  on  the  edges  of  the  reel 
rolls,  while  too  much  crown  will  cause  soft  spots  in  the  middle  of 
the  reel  rolls;  in  either  case,  all  the  press  rolls  should  be  calipered 
with  micrometer  calipers,  and  the  faulty  roll  should  be  re-ground 
when  the  machine  is  shut  down.  The  temporary  remedy  in 
either  case  is  to  hang  more  weights  on  the  press-roll  levers  on  the 
side  where  the  paper  is  too  thick,  or  to  reduce  the  weight  on  the 
side  where  it  is  too  thin.  This  change  must  be  effected  gradually. 
The  trouble  may  originate  at  the  slices,  one  side  of  which  is 
probably  too  high.  If  the  variation  in  thickness  is  due  to  vari- 
ation at  the  center,  the  trouble  may  be  due  to  a  sag  at  the  center 
of  the  slice,  or  to  incorrect  crowning  of  a  press  roll.  The  last 
chance  to  change  the  relative  thickness  of  the  two  edges  of  the 
paper  is  at  the  calenders.  Here  there  is  a  compound-lever 
system  on  either  side  of  the  machine,  similar  to  that  on  the  press 
rolls.  In  order  to  get  the  desired  results,  care  and  thought  must 
be  used  in  changing  the  weights. 

288.  Causes  of  Breaks. — Should  the  paper  break  between  the 
calender  rolls,  examine  the  paper  between  the  press  rolls.  First 
see  if  it  is  too  tight,  especially  between  the  couch  and  the  first 
press  and  between  the  first  and  second  presses,  where  the  paper 


§6  CALENDERS,  SLITTERS  AND  WINDERS         185 

is  weak  and  easily  over-strained.  If  the  paper  is  not  too  tight 
between  the  presses,  the  trouble  is  probablj^  caused  b}-  a  dirty 
wire;  some  of  the  meshes  may  be  filled  up  with  dirt,  which  keeps 
the  suction  boxes  from  pulling  at  these  points,  and  weak  spots 
occur  in  the  paper. 

Sometimes  the  wire  seam  is  raised;  in  such  a  case,  make  a  note 
to  correct  this,  but  tighten  up  the  wire  temporarily  by  means  of 
the  stretch  roll.  Look  at  the  wet  felts  for  dried  stuff  or  hard 
spots;  these  can  sometimes  be  located  by  examining  the  paper 
for  small,  dark  marks  and  spots,  as  it  passes  from  the  press  to 
the  drj^ers.  If  felt  spots  cause  the  breaking,  the  cause  can  also 
be  identified  by  the  presence  of  these  spots  at  the  broken  edge. 
These  spots  can  often  be  removed  by  the  careful  use  of  a  piece 
of  wool  card,  which  is  a  sort  of  wire  brush  that  is  used  for 
carding  wool. 

Breaking  at  the  calenders  can  be  caused  by  having  the  draws 
so  slack  that  the  edges  crease  at  the  nip  of  the  press  rolls;  the 
calenders  press  these  creases  into  cracks. 

Breaks  at  the  calenders  are  often  caused  by  having  the  paper 
too  slack  between  the  dryers;  the  tight  dryer  felts  will  then 
crease  the  paper  at  the  edges,  and  it  will  break  at  the  calenders. 
It  is  better  to  keep  the  first  dryer  cylinder  cooler  than  the  others, 
in  order  to  start  the  heating  and  drying  of  the  paper 
gradually. 

289.  Determining  the  Accuracy  of  the  Crowning. — The 
machine  tender  can  make  an  approximate  estimate  of  the 
accuracy  of  the  crowning  on  the  press  rolls  when  the  machine  is 
idle,  by  looking  through  the  nip,  to  see  if  fight  shows  between  the 
rolls,  at  the  middle,  at  the  ends,  or  irregularly;  and  from  this 
inspection,  he  may  form  an  opinion  as  to  whether  the  crowning 
is  a  cause  of  any  trouble  he  may  be  having  at  the  calenders.  If 
the  press  rolls  do  not  look  good  to  him,  the  next  step  is  to  take 
out  the  top  rolls  and  caKper  the  bottom  roll;  should  the  calipering 
confirm  the  machine  tender  in  his  opinion  that  the  crowning  is 
wrong,  the  roll  should  be  ground  in  accordance  with  the  measure- 
ments it  ought  to  have.  With  a  stack  of  calenders,  however,  it  is 
not  feasible  to  estimate  whether  the  rolls  have  the  proper  crown- 
ing by  looking  between  the  bottom  roll  and  that  next  above  it 
when  the  stack  is  idle;  it  is  necessary  to  have  the  rolls  turning 
when  endeavoring  to  determine  by  this  method  whether  there  is 
any  error  in  the  crowning. 


186  PAPER-MAKING  MACHINES  §6 

Referring  to  Fig.  73,  the  arrow  indicates  that  the  bottom  roll  is 
turning  clockwise,  while  the  roll  next  above  is  turning  counter- 
clockwise. The  bottom  roll  is  driven,  and  it  drives  the  rest  of 
the  stack  by  surface  friction.  This  action  of  the  surface  driving 
tends  to  push  the  second  roll  to  the  right  in  a  horizontal  direction, 
and  the  reaction  of  the  second  roll  to  the  push  it  tends  to  give  the 
third  roll  (a  push  to  the  left),  combined  with  the  force  to  right 
exerted  by  the  first  roll,  tends  to,  and  does,  deflect  (bend)  the 
second  roll,  which  causes  it  to  leave  its  line  of  contact  with  the 
lower  roll,  unless  the  lower  roll  has  been  so  crowned  as  to  prevent 
this.  Consequently,  while  the  rolls  might  have  perfect  contact 
when  idle,  the  contact  might  be  very  bad  when  running.  When 
specifying  the  crowning  of  the  lower  roll,  the  horizontal  bending 
of  the  second  roll  must  receive  as  much  consideration  as  the  ver- 
tical bending  due  to  the  weight  of  all  the  other  rolls. 

Any  calender  stack  may  show  light  only  between  the  ends  of  the 
rolls  when  standing  still,  as  though  the  crowning  were  too  much, 
and  yet  show  light  only  in  the  middle  when  running,  because  the 
crowning  of  the  bottom  roll  is  actually  insufficient.  If  there  is  too 
little  crown,  the  reel  rolls  are  soft  at  the  ends;  if  there  is  too  much 
crown,  the  reel  rolls  are  soft  in  the  middle  and  hard  at  the  ends. 

The  second  calender  roll,  counting  from  the  bottom,  is  made 
larger  in  diameter  than  the  other  intermediate  rolls,  to  make  it 
stiff  enough  to  resist  the  deflection  (bending)  due  to  driving. 
The  top  calender  roll  is  made  larger  than  the  intermediate  rolls,  so 
it  will  give  sufficient  pressure  on  the  first  nip  to  form  the  sur- 
face of  the  paper  and  force  any  loose  fibers  into  the  paper.  The 
top  and  intermediate  calender  rolls  are  not  crowned;  but  the 
general  shop  practice  is  to  make  certain  that  they  are  not  hollow 
ground,  by  making  them  a  trifle  (say  a  thousandth  of  an  inch) 
larger  in  diameter  at  the  middle  than  at  the  ends. 

290.  Variation  in  Finish. — The  surface  of  the  paper  can  be 
varied  considerably  by  changing  the  pressure  of  the  calenders  and 
the  number  of  rolls  used.  Calender  frames  are  fitted  with  a 
pair  of  long  vertical  screws  on  either  end.  One  or  more  rolls  can 
be  lifted  out  of  commission  by  pulling  up  a  yoke  under  each  journal 
of  the  lowest  roll  to  be  lifted,  by  turning  screws  whose  threads 
pass  through  threaded  holes  in  the  yokes.  As  the  screws  are 
stationary,  except  for  turning,  the  yoke  acts  like  a  nut;  and  as  it 
rises,  it  carries  the  rolls  with  it.  Other  means  are  also  used  for 
raising  calender  rolls. 


§6  CALENDERS,  SLITTERS  AND  WINDERS         187 

For  extra-high  finish  without  the  use  of  supercalenders,  some 
machines  are  equipped  with  more  than  one  stack.  If  a  rough, 
antique  finish  is  desired,  calenders  may  be  omitted  entirely. 

When  paper  is  first  put  through  the  stack,  there  may  be  small 
pieces  of  paper  stuck  to  the  rolls,  and  these  will  mark  the  paper 
if  not  removed.  The  remedy  is  to  throw  some  water  or  kerosene 
on  the  stack,  or  to  scrape  the  paper  off  with  a  calender  scraper; 
the  doctor  blade  will  take  off  most  of  the  pieces.  If  paper  winds 
around  a  roll,  an  experienced  man  can  cut  it  off,  but  this  is 
dangerous;  the  best  way  is  to  stop  the  machine  (stack)  and  cut 
it  away. 

The  friction  incident  to  calendering  generates  much  heat;  and 
since  this  might  become  excessive,  it  is  customary  to  cool  the 
calenders  with  a  blast  of  cold  air.  The  air  is  led  in  by  a  horizontal 
duct,  which  extends  across  the  machine  behind  the  bottom  calen- 
der roll;  it  is  distributed  by  a  set  of  vertical  pipes,  from  which 
elbows  direct  the  blast  against  the  calenders. 


REELS,  SLITTERS  AND  WINDERS 


TYPES  OF  REELS 

291.  Four-Drum  Revolving  Reel. — From  the  breast  roll  to 
the  calenders,  the  manufacture  of  paper  is  a  continuous  process; 
but  after  the  paper  leaves  the  calenders,  it  must  be  gotten  into  a 
form  that  can  be  readily  handled.  To  accomplish  this  result,  it 
is  generally  necessary  to  trim  the  edges  and  slit  the  sheet  into 
several  strips;  and  the  first  step  in  this  process  is  to  wind  the 
paper  on  a  reel.  There  are  a  number  of  types  of  reels  and 
winders,  several  of  which  will  now  be  described. 

A  four-drum  revolving  reel  A  is  shown  in  Fig.  74.  Here  the 
paper  is  wound  up  on  one  reel  cylinder  and  is  reeled  off  the 
opposite  cjdinder  at  the  same  time;  this  allows  the  winder  to 
keep  up  with  the  paper  machine,  while  giving  time  for  removing 
a  finished  roll  from  the  winder  B  and  starting  another  roll.  The 
peripheral  speed  of  the  winder  rolls  must  be  greater  than  the 
speed  of  the  paper  through  the  machine;  this  is  to  provide  for 
unavoidable  delays  in  changing  rolls,  setting  slitters,  starting  the 
winder,  mending  breaks,  etc. 


188 


PAPER-MAKING  MACHINES 


§6 


292.  The  English  Reel. — A  type  of  peripheral,  or  surface,  drive 
reel,  sometimes  called  an  English  reel,  is  shown  in  Fig.  75,  the 
paper  being  wound  around  the  core  by  reason  of  the  friction 
between  it  and  the  revolving  drum.  The  large  drum  F  is  driven 
mechanically,  and  it  is  therefore  always  turning.     An  arm  H, 


Fig.  74. 

holding  a  core  K,  with  the  paper  wrapped  on  it,  is  lowered  by  the 
wheel  and  gear  W,  so  that  the  paper  on  the  core  rests  on  the  large 
revolving  drum;  the  result  is  that  the  paper  and  core  are  forced 
to  revolve  around  the  core  bearings,  and  this  winds  the  paper  on 
the  core.     The  paper  roll  gets  larger  and  larger,  but  it  cannot 


Fig.  75. 

wind  up  faster  or  slower  than  the  peripheral  speed  of  the  large 
revolving  drum.  This  reel  has  the  advantage  of  making  reel 
rolls  that  are  tight  and  uniform,  and  it  therefore  helps  in  making  a 
good  roll  on  the  winder. 

Fig.  75  also  shows  a  reeling-off  stand  (see  also  Fig.  80),  the  roll 
of  paper  being  taken  out  of  the  reel  at  A  and  placed  in  this 


§6  CALENDERS,  SLITTERS  AND  WINDERS         189 

stand,  preparatory  to  being  run  through  the  slitters  and  onto 
the  winder.  In  both  Figs.  74  and  75,  the  reel  is  shown  at  A,  the 
winder  at  B,  and  the  slitters  at  D. 

293.  Transferring  the  Paper. — Skill  is  required  to  transfer  the 
paper  from  the  calenders  to  the  reel.  On  fast  machines,  when 
one  reel  is  full,  an  empty  reel  is  "struck in, " i.e.,  connected.  The 
back  tender  or  third  hand  holds  a  knife  against  the  paper  on  the 
last  calender  roll;  this  cuts  a  narrow  strip,  which  his  helper  pulls 
off  and  winds  around  a  new  reel,  draws  tight,  and  tucks  the  free 
end  between  the  sheet  and  the  reel  (keeping  his  fingers  out  of  the 
nip),  while  the  knife  is  carried  across  the  sheet.  At  once,  the 
paper  is  winding  full  width  on  the  reel. 

On  slow  machines,  the  back  tender  or  third  hand  stands  on  the 
front  side  of  the  sheet  and  his  helper  stands  at  the  back.  One 
hand  grasps  the  edge  of  the  paper  near  the  calenders  and  snaps 
the  paper  across,  or  else  he  cuts  it  with  a  stick  that  is  held  in  the 
free  hand.  The  two  men  now  pass  the  paper  under  the  reel, 
catch  it  on  the  other  side,  draw  the  slack  tight,  and  then  tuck  it 
in.  The  tension  of  the  reel  belt  is  carefully  adjusted  at  once,  so 
the  paper  draws  tight  without  wrinkling.  The  full  roll  is  "struck 
out"  as  soon  as  possible. 

When  a  new  roll  is  built  up  on  a  roll  that  is  driven,  the  tendency 
is  for  the  surface  to  travel  faster  and  faster;  in  the  present  case, 
this  is  an  impossible  condition  of  affairs,  since  the  paper  speed  is 
constant,  and  one  of  two  things  must  happen;  the  paper  must 
break,  or  the  reel  speed  must  change.  The  latter  may  be  effected 
by  driving  the  reel  with  a  belt,  the  tension  of  which  can  be  so  varied 
as  to  allow  it  to  slip  more  or  less.  This  operation  must  be 
performed  carefully  and  frequently;  otherwise,  if  the  pull  on  the 
paper  increases  or  varies  too  much,  the  roll  will  get  soft,  or  it 
will  pull  so  tight  as  to  make  it  slip  at  the  center. 

294.  Two-Drum  Upright  Reel. — A  two-drum  upright  reel  is 
shown  in  Fig.  76.  While  the  paper  is  being  reeled  onto  one  of  the 
drums  from  the  calenders,  it  is  being  reeled  off  the  other  drum 
onto  the  slitters  and  winder.  The  reel  is  driven  by  a  belt  on 
pulley  P;  and  on  the  same  shaft  that  carries  P  is  keyed  the  main 
driving  gear  F,  which  is  in  mesh  with  the  gears  G,  G.  The 
driven  gears  ride  loose  on  their  shafts  until  the  clutches  C,  C 
are  thrown  in  by  the  operator  at  the  front  side  of  the  machine, 
by  means  of  the  clutch  levers  L,  L.     The  reel  drums  D,  D  can 


190 


PAPER-MAKING  MACHINES 


i6 


be  lifted  out  of  their  bearings,  when  it  is  desired  to  useareehng-off 
stand  or  to  repair  the  drums.  The  front  bearings  B,  B,  which 
carry  the  driving  shaft,  are  adjustable  by  means  of  the  hand 
wheels  H,  H,  to  correct  for  any  inaccuracy  in  the  way  the  paper 
reels;  that  is,  if  the  paper  tend  to  travel  to  one  end  of  the  drum, 
or  if  it  tend  to  wrinkle,  this  can  be  corrected  usually  by  moving 
the  front  bearing  forward  or  back.  If  the  paper  is  pulling  too 
tight,  the  tension  on  the  sUp  belt  is  lessened  a  little. 


Fig.  76. 


295.  If  a  spiral  wrinkle  persist  in  forming,  the  reel  journals 
may  be  a  little  out  of  line ;  in  which  case,  move  the  bearing  toward 
the  head  of  the  wrinkle,  slightly  toward  the  calenders.  A 
smooth  piece  of  plank,  held  against  the  wrinkle,  will  sometimes 
eliminate  it. 

296.  Improperly  Wound  Rolls. — When  a  roll  is  soft  at  the 
center,  it  is  likely  to  slide  on  the  reel;  this  is  often  due  to  the 
outside  being  wound  too  tight.  Old  timers  will  sometimes 
correct  this  by  nailing  a  piece  of  board  on  the  reel;  but  the  safest 
way  is  to  start  a  new  reel,  and  get  it  sufficiently  tight  at  the  start. 
A  slipped  roll  is  a  difficult  proposition  for  the  winder,  and  it 
usually  makes  poor  rolls,  unless  re-wound  very  carefully. 

297.  Controlling  Paper  Tension. — When  the  paper  is  being 
unreeled,  the  operator  can  control  its  tension  by  means  of  the 
brakes  K  on  the  pulleys  at  the  front  end  of  the  drum  shafts, 
Fig.  76.  The  brakes  are  straps  that  pass  nearly  around  the 
pulleys,  and  they  can  be  so  tightened  or  loosened  by  means  of 
hand  wheels  that  the  work  done  by  the  winder  is  made  heavy  or 
light,  thus  controlling  the  tension  of  the  paper  to  the  winder  and 
the  tightness  of  the  roll.  The  tension  of  the  paper  from  the 
calenders,  as  it  is  reeled  onto  the  drums,  is  also  controlled  by  the 
brakes,  as  well  as  by  the  tension  of  the  driving  belt  on  pulley  P. 


§6 


CALENDERS,  SLITTERS  AND  WINDERS         191 


298.  Three -Drum  Reels. — A  three-drum  upright  reel  is 
shown  in  Fig.  77.  Since  hke  parts  are  here  lettered  the  same  as 
with  the  two-reel  drum  of  Fig.  76,  the  explanation  of  the  latter  as 
previously  given  will  suffice  also  for  this  case.  The  only  essential 
difference  between  the  two  is  in  the  gearing,  an  idler  /  being 
used  to  gear  together  the  two  top-drum  shafts;  this  is  used  in 
order  to  keep  the  three  drums  revolving  in  the  same  direction 
when  the  clutches  are  in.  In  the  case  of  both  the  two-drum  and 
three-drum  reels,  the  large  hand  wheels  W,  shown  on  the  front 
side  of  the  machine  on  each  drum  shaft,  are  for  the  purpose  of 
starting  the  paper  on  the  drum,  by  wrapping  by  hand  a  few 


Fig.  77. 


turns  of  paper  before  putting  in  the  clutch;  also  to  give  the  paper 
a  start  in  threading  the  winder.  The  principal  advantage  in  3 
drums  is  in  reducing  the  chances  for  having  no  empty  reel  when  a 
new  roll  must  be  started,  should  there  be  trouble  with  a  stripped 
roll  or  the  winder. 

In  Fig.  78  is  shown  a  design  of  a  three-drum  revolving  reel 
that  is  similar  in  details  to  the  four-drum  reel  shown  in  Fig.  74. 
In  so  far  as  is  possible,  corresponding  parts  are  lettered  the 
same  as  in  Figs.  76  and  77,  which  show  upright  reels,  and  this 
design  may  be  compared  with  those.  The  levers  L  are  for  the 
purpose  of  throwing  out  the  clutches  C  on  the  drum  shafts,  so 
that  the  gears  F  that  mesh  with  the  large  driving  gear  G  will 
cease  to  turn  the  drums  when  they  are  not  winding  paper. 
Gears  F  are  loose  on  the  drum  shaft,  but  the  clutch  is  kej'ed  to  it. 
The  large  driving  gear  G  is  itself  driven  by  the  small  gear 


192 


PAPER-MAKING  MACHINES 


s^-! 

^ 

fe 

i 

n 

is 

^     1  1 

u 

§6  CALENDERS,  SLITTERS  AND  WINDERS         103 

0,  which  is  on  the  driving  shaft  S;  the  latter  carries  a  pulley  P, 
which  is  driven  by  a  slip  belt.  The  tension  of  the  paper  is 
controlled  in  the  same  way  as  in  the  case  of  an  upright  reel,  by 
properl}'  proportioning  the  tightness  of  the  shp  belt  and  the 
brakes  J  on  the  brake  wheels  K.  The  slip  belt  can  be  tightened 
to  pull  the  load  easily;  then  the  brake  is  so  adjusted  that  the 
belt  must  exert  a  somewhat  greater  pull  on  the  load,  so  the  pull 
on  the  paper  will  not  be  too  hard.  On  this  reel,  as  on  any  other, 
if  no  unreeling  stand  is  used,  the  bearings  carrying  the  rolls  of 
paper  on  the  reel  can  be  used  for  unreeling,  so  long  as  the  clutch 
C  is  not  in,  and  the  drum  shaft  turns  idly  in  gear  F. 

299.  Revolving  the  Reel  Drums. — A  revolving  reel,  whether 
two-drum,  three-drum,  four-drum,  or  six-drum,  or  any  number 
of  drums,  must  so  revolve  that  everj^  drum  can  be  placed  in  the 
most  convenient  position  for  reeling  or  unreeling  the  paper. 
For  reehng  paper,  the  drum  must  be  near  the  calender  and, 
for  unreeling  or  changing  drums,  near  the  winder. 

The  method  of  revolving  the  three-drum  reel  shown  in  Fig. 
78  is  evident,  and  all  revolving  reels  are  caused  to  turn  in 
practically  the  same  manner.  When  a  roll  of  paper  is  to  be 
reeled  up  or  reeled  off,  as  the  case  may  be,  and  it  is  time  to  move 
the  drums  around  and  bring  the  next  drum  in  position  to  reel  or 
unreel  paper,  the  big  lever  A  (see  end  view)  is  thrown  over;  this 
turns  shaft  V,  and  lever  R  (which  is  keyed  to  shaft  V)  pulls  on 
the  end  of  link  Q.  The  other  end  of  link  Q  is  pinned  to  an  arm 
on  the  upright  shaft  H;  and,  when  Q  moves,  shaft  H  is  caused  to 
turn  in  its  bearings.  Clutch  lever  M  is  also  keyed  to  shaft  H; 
thus  when  H  is  turned,  the  clutch  M  is  thrown  into  clutch 
pulley  iV,  which  is  driven  by  a  belt  and  is  loose  on  shaft  T  (see 
end  view),  to  which  is  keyed  the  small  gear  E.  Gear  E  meshes 
with  gear  £",  which  is  on  a  short  shaft  that  carries  the  worm  W, 
which  meshes  with  the  worm  wheel  W .  The  worm  wheel  W  is 
keyed  to  the  large  central  shaft  that  carries  the  large  revolving 
spiders  Y,  Y,  which  hold  the  bearings  of  the  drum  shafts. 
Since  clutch  pulley  N  is  always  turning,  it  follows  that  when 
clutch  M  is  thrown  in  b}'  lever  A,  shaft  T  is  forced  to  turn  also; 
this  causes  gears  E  and  E'  and  worm  W  to  turn,  and  it  imparts 
a  slow  rotative  movement  to  worm  wheel  W\  which  causes  the 
three  drums  to  rotate  slowly  until  an  empty  drum  is  in  the 
receiving  position.     Lever  A  is  then  thrown  back  to  its  former 


194 


PAPER-MAKING  MACHINES 


§6 


position,  clutch  M  is  thereby  thrown  out,  and  the  drums  stop 
their  rotative  movement. 

The  type  of  gearing  employed  in  revolving  reels  may  vary, 
but  the  general  principles  of  design  and  operation  are  as  just 
described. 

300.  The  Slip-Belt  Drive. — A  type  of  drive,  called  a  slip-belt 
drive,  is  shown  in  Fig.  79;  it  illustrates  the  principle  of  the  drive 
that  is  very  generally  used  on  reels  and  winders.  It  is  necessary 
to  describe  the  reel  drive  here,  so  the  effect  of  the  drive  on  the 
operation  of  the   reel   may  be  understood.     With  this  drive. 


Fig.  79. 

the  tension  of  the  driving  belt  B  and,  what  is  more  important,  the 
amount  of  lap  around  the  driven  pulley  P  may  be  varied  by 
means  of  a  tightener.  When  the  tightener  T  is  out  altogether, 
the  belt  hangs  idly  on  the  top,  or  driven,  pulley  P,  and  the 
bottom  loop  does  not  touch  the  driving  pulley  D,  which  therefore 
turns  idly.  Pulley  M  is  keyed  to  the  same  shaft  as  pulley  D, 
and  is  driven  from  the  variable-speed  shaft  or  by  a  motor.  As 
the  tightener  is  pulled  in  by  the  action  of  the  lever  L,  the  lever 
being  held  in  position  at  any  point  that  gives  the  required  belt 
tension  by  means  of  the  quadrant  and  pinion  shown,  the  tension 
of  the  belt  can  be  varied  from  nothing  (in  the  idle  position)  to 
the  maximum  tension  that  the  operator  can  give  it,  up  to  the 
limit  of  his  strength.  When  the  belt  is  comparatively  loose,  it 
slips  on  the  driven  pulley;  in  such  case,  the  speed  of  the  reel 
drums  D,  Fig.  76,  is  slow,  the  tension  of  the  paper  is  slight,  and 


§6 


CALENDERS,  SLITTERS  AND  WINDERS         195 


the  tightness  of  the  brakes  K  is  small.  By  tightening  the  driving 
belt,  the  machine  tender  can  increase  the  pull  by  the  drums  on 
the  paper  from  the  calenders;  but  should  the  tension  get  too 
high,  he  can  correct  this  by  tightening  the  brake  straps  K. 
This  should  be  avoided,  however,  as  it  is  a  waste  of  power. 

301.  Unreeling,  or  Reeling-Off,  Stands. — An  unreeling  stand, 
also  called  a  reeling-ofif  stand,  is  shown  in  Fig.  80;  an  unreeling 
stand  is  always  used  with  the  friction  type  of  reel.  The  reel 
drum,  with  its  roll  of  paper  R  on  it,  is  taken  off  the  reel  by  use  of  a 
compressed-air  or  electric  hoist,  and  it  is  placed  in  the  bearings 
of  the  unreeling  stand.  An  unreeling  stand  is  never  driven, 
the  paper  being  pulled  off  by  the  winder;  consequently,  the  roll 


R 


Fig.  80. 

on  the  winder  grows  larger,  the  roll  on  the  unreeling  stand  grows 
smaller,  and  the  tension  of  the  paper  between  the  two  varies 
greatly,  being  heavy  at  first  and,  finally,  very  light.  The  brake 
K  is  used  to  control  the  paper  tension  by  means  of  the  thumb 
nut  T,  whenever  the  winder  man  wishes  to  alter  it;  by  keeping 
the  tension  fairly  uniform,  the  re-wound  roll  is  kept  hard  all  the 
way  through.  The  position  of  the  reel  drum  is  so  adjusted  by 
the  hand  wheels  M  and  N  that  the  paper  will  run  true  to  the 
winder.  The  eyebolts  H,  which  hook  to  lifting  chains  on  the 
hoist,  are  tapped  into  square  blocks  B  that  fit  into  the  unreeling- 
stand  brackets  C;  these  blocks  have  bushed  bearings,  and  slip 
over  the  drum  journals  /,  or  the  bearings  may  be  split. 

302.  The  Brake  Bands. — The  brake  bands  on  unreeling 
stands  and  reels  are  subjected  to  very  severe  service  when  they 
are  controlling  the  tension  of  the  paper  to  a  high-speed  winder, 
say  when  winding  the  paper  at  a  speed  of  2000  feet  per  minute, 
more  or  less,  and  the  high  speed  of  the  pulley  within  the  stationary 
brake  band  will  soon  burn  out  a  leather  strap.  These  pulleys 
should  be  very  wide  and  large  in  diameter,  so  as  to  have  ample 
brake  surface.     A  pulley  of  large  diameter  will  have  a  high 


196 


PAPER-MAKING  MACHINES 


§6 


peripheral  speed  when  revolving  swiftly,  but  it  takes  less  force  to 
slow  it  or  stop  it.  Consequently,  if  trouble  be  experienced  with 
brake  bands,  install  a  wide-faced  pulley  of  large  diameter;  then 
the  resulting  large  surface  area  will  carry  away  the  heat  that  is 
generated.  With  such  a  pulley,  a  small  pressure  per  unit  of 
area  of  brake  will  control  the  operation  of  unreeling.  If  the 
brake  pulley  is  large  enough,  leather  may  be  used  for  the  brake 
band;  but  an  asbestos  brake  band  might  be  better. 


SLITTERS  AND  WINDERS 

303.  Description  of  Slitter. — Slitters  are  revolving  disks  that 
cut  the  paper  into  strips  as  it  passes  on  its  way  to  the  winder.     A 


Fig.  81. 


slitting  machine  and  a  winder  are  shown  in  Fig.  81.  The  paper 
passes  from  the  reel  drum  and  under  the  adjustable  roll  B,  which 
is  often  supported  in  spring  bearings,  in  a  manner  similar  to  the 
spring  roll  between  the  drj^ers  and  calenders.  From  under  roll 
B,  the  paper  passes  over  roll  J  and  slitter  board  T,  being  thus 
kept  lying  smooth  and  even  as  it  enters  between  the  slitter  disks 


§6  CALENDERS,  SLITTERS  AND  WINDERS         197 

D  and  E     After  being  sUt  into  strips  of  the  widths  required,  the 
stnps  of  paper  are  carefully  placed  over  the  curved  plate  (or  rout 

'  ^        "^'"?  *'"'  P'^P"''  8*^  to  the  winder.     When  a  roll   s 
used  mstead  of  the  plate  F,  it  may  revolve  or  it  may  be  stationary 
accordmg  to  the  design.     The  roll  B  is  so  adjusted  as  to  obtainTn 
even  tension  the  full  width  of  the  sheet,  and  to  prevent  wrllJZ 

304  The  SUtter  Disks.-Two  views  of  the  slitter  disks  D  and  E 
are  shown  ,n  Fig.  82.  The  horizontal  distance  between  the 
adjace  t  ,,tt,,  ^isks  is  obtained  roughly  by  turning  the  hand 
the  c  o^s  hafVlth^"  '  'V'^*  *""  ^  '^  -curely  fastened  to 

siif err  TeV^ri-:r  reS: -fsS^^^^^^^^ 

and  clamp  K.  The  position  of  clamp  H  is  such  that  when  lever 
i  IS  m  he  position  shown,  disk  D  h  pressed  against  the  revolving 
lower  slitter  disk  by  spring  ,S.  When  the  top  of  lever  L  is  th roZ 
over  to  the  left  nearly  90°  from  the  position  shown  the  a  e  7o" 
the  bell-erank  lever  is  forced  against  the  annular  ii;nge  B     Thl 

sprmg  S.  When  lever  L  is  returned  to  its  original  position 
Bprmg  5  pushes  disk  D  back  to  the  position  shown  in  Rg  82' 
The  lower  disk  E 15  made  fast  to  the  slitter  shaft  V,  Fig  81  at  the 
proper  pomt  for  slitting  the  paper. 

th  J^/T'  I'/"'  ?"''"  '"■'  "°8"  °f  ^'"'t  iron  or  steel,  turned  on 
the  outside  and  faced  on  the  end  touched  by  the  upper  disk  thus 
giving  a  sharp  edge  for  the  upper  disk  to  work  again  t  The 
ower  disks  are  clamped  on  the  slitter  shaft,  or  ele  they  are 
fastened  on  it  by  headless  set  screws  JV,  Fig.  82;  other  kinds  o 
screws  are  not  safe.  The  .slitter  shnft  t-  ir:  01  •  "".■"""»  °' 
it  rBvnN,^o  :  *  (■  .  ne  siittei  shaft  1  ,  Fig.  81,  is  so  driven  that 
It  revolve  just  fast  enough  to  insure  the  proper  speed  to  theedges 

contact  w  r.f  f "  '^'''"  ''"'  "PP"  ^"tters  are  brought  into 
contact  with  the  lower  ones,  the  springs  S  exert  sufficient  pressure 
to  cause  the  upper  slitters  to  revolve  at  the  same  speed  as  the 
lower  shtters.  When  the  slitters  are  not  in  contact  the  paper 
passes  over  the  lower  slitters  and  under  the  upper  shttjrs  wiZu 

have1»  T  '"'"^'^-  P"  ^'^^-'P'"''^  -"Chines,  it  is  better  to 
The  dT  "-".fitter  disks,  say  8  inches  or  lOinches  in  diameter. 

soon  t?    f  Tl    ""'"  f  ""'■  *^''^  '^  "^^t,  at  high  speeds,  they 
oon  get  out  of  dynamic  balance  and,  therefore,  cut  irregularly; 

E  Ttt°     '°  '"'  ''  '"'■''''''  ^^  P""'  ''''"'"°''=  '"''''"<=«  ^'  the 


198 


PAPER-MAKING  MACHINES 


§6 


Slitter  disks  should  be  kept  sharp,  and  their  edges  should  travel 
at  least  10%  faster  than  the  paper;  if  their  speed  is  slower  than 
this,  or  is  about  the  same  as  that  of  the  paper,  they  will  not  cut 


Fig.  82. 

clean.     The  lower  slitter  disks  should  be  so  placed  that  they  pro- 
ject above  the  slitter  board  T,  Fig.  81,  not  more  than  ,V  inch. 

The  shavings  usually  fall  clear  of  the  slitter,  and  can  pass 
through  pipes  in  the  floor  to  a  broke  beater  below,  or  they  may 
be  carried  by  compressed  air  to  the  tending  side  and  put  in  a  ear. 


§6 


CALENDERS,  SLITTERS  AND  WINDERS         199 


A  narrow  shaving  may  wind  up  on  the  sHtter  shaft;  it  is  dangerous 
to  cut  this  off  without  stopping  the  winder. 

305.  The  Score  Cutter. — The  sHtter  is  not  always  in  the  posi- 
tion shown  in  Fig.  81,  nor  is  it  always  of  the  type  shown  in  Fig. 
82.  A  type  that  differs  very  markedly  from  that  just  described 
is  shown  in  Fig.  83.  Here  A  is  the  roll  of  paper  to  be  unreeled  and 
re-wound;  P  is  the  re-wound  roll,  which  rests  on  the  winder 
rolls  Wi  and  "Pf^;  G  is  a  guide  roll;  and  *S  is  the  cutter.  Winder 
roll  Tf  1  has  its  surface  hardened.  Cutter  S  has  a  V-shaped  edge, 
and  is  held  against  the  hardened  winder  roll  Wi  b}^  strong  springs ; 
it  cuts  the  paper  by  scoring  it,  instead  of  by  shearing  it,  as  in  the 
case  of  the  slitter  last  described.     The  paper  passes  from  roll  A 


Fig.  83. 


over  the  guide  roll  G,  between  the  score  cutter  S  and  the  winder 
roll  Wi,  and  then  onto  the  paper  roll  P,  where  it  is  wound  up. 
The  small  roll  R  is  for  the  purpose  of  straightening  and  tightening 
the  roll  when  first  started ;  this  roll  is  not  always  used.  Sometimes 
a  separate  cutter  roll,  for  the  score  cutter  to  press  against,  is 
used,  as  when  the  winder  roll  is  so  large  that  it  would  be  very 
costly  to  harden  it.  As  before  stated,  these  slitters  cut  the  paper 
by  scoring  it;  a  clean,  straight  cut  and  well-separated  rolls  are 
obtained. 

306.  Two-Drum  Winder.— The  slitter,  of  either  type,  and 
winder  are  often  combined  in  one  machine,  the  slitters  and  the 
winder  drums  being  supported  on  the  same  frame  instead  of 
separately,  as  was  shown  in  Fig.  81  (for  convenience  in  describ- 
ing), which  also  shows  a  two-drum  winder  to  the  left  of  the 
shtter.  As  it  leaves  the  slitters.  Fig  81,  the  paper  passes  over  the 
spreader  bar  A,  which  presents    a  smooth,    rounded  surface    to 


200  PAPER-MAKING  MACHINES  §6 

support  the  paper.  The  height  of  the  bar  can  be  adjusted  to 
suit  the  run  of  the  paper,  by  moving  the  brackets  either  up  or 
down,  and  by  adjusting  the  hand  screws  at  either  end.  The 
inchnation  of  the  paper  to  sag  or  to  vibrate  vertically  can  thus 
be  corrected.  The  bar  A  is  bent,  so  it  will  lift  the  paper  at  the 
center  slightly  and  separate  the  strips,  thus  keeping  the  edges 
from  interlocking  while  winding  into  rolls. 

The  operator  passes  the  paper  under  the  winder  and  up 
between  the  winder  drums  W  and  W,  one  or  both  of  which  may  be 
driven.  The  paper  is  then  wrapped  around  the  cores  C;  these  are 
usually  3-inch  pipes  (iron  or  paper),  with  notched  ends,  which 
slip  over  a  core  shaft  C,  and  are  held  in  position  by  collars. 
Shaft  C  is  carried  in  the  bearings  shown,  which  are  attached  to  the 
free  end  of  the  chain  L.  By  taking  off  thumb  screw  X,  the  bear- 
ings open  on  hinges,  which  enables  the  cores  to  be  slipped  over 
the  core  shaft.  Wooden  cores  have  square  holes  and  fit  over  a 
square  shaft.  As  the  roll  gets  larger,  the  core  rises,  and  the  final 
position  of  the  bearing  and  of  the  finished  roll  is  indicated  by  C 
and  the  dotted  circle  r. 

The  arrows  show  the  directions  in  which  the  winder  drums 
revolve.  It  is  important  that  the  end  drum  of  the  paper  machine 
shall  revolve  outward  on  top,  to  guard  against  the  danger  of  a 
man's  hand  being  drawn  under  the  paper  roll. 

307.  Starting  the  Roll. — When  starting  a  roll,  many  paper 
makers  consider  it  easier  to  pass  the  paper  under  both  winder 
rolls,  bring  it  up  over  the  second  roll,  and  then  under  the  core; 
this  means  that  the  winder  drums  must  revolve  in  a  direction 
opposite  to  that  indicated  by  the  arrows  in  Fig.  81.  When  this 
method  of  winding  is  used,  a  fender  or  safet}^  guard  should  be 
placed  after  the  second  winder  drum  W,  so  as  to  guard  a  man, 
should  he  fall  in  such  a  manner  that  his  hands  might  get  caught  in 
the  nip. 

308.  Driving  the  Winder. — The  winder  is  usually  driven 
independently  of  the  paper-machine  drive,  in  order  that  the 
starting  and  stopping  of  the  winder  may  not  cause  variations  in 
the  speed  of  the  machine  and  in  the  weight  of  the  paper ;  when  uni- 
form thickness  of  paper  is  essential,  this  is  important. 

As  the  paper  roll  winds  up,  it  increases  in  diameter.  But  since 
the  paper  here  winds  because  of  its  contact  with  the  surface  of  the 
winder  drums,  the  paper  rolls  are  kept  tight.     The  paper  also 


§6  CALENDERS,  SLITTERS  AND  WINDERS         201 

winds  at  a  constant  speed;  for  whch  reason,  this  type  of  winder 
drum  is  called  a  constant-speed  winder. 

309.  Maintaining  Constant  Pressure  on  Drums. — As  the  paper 
roll  r  increases  in  size  (see  Fig.  81),  the  weight  on  the  drums  also 
increases;  for  this  reason,  some  makers  have  devised  means  of 
relieving  somewhat  the  additional  pressure  on  the  drums.  In 
connection  with  the  winder  shown  in  Fig.  81,  a  cord  or  chain 
suspends  weights  U'  from  arms  M  attached  to  the  shaft  U,  which 
carries  the  sprocket  wheels  for  chains  L.  As  the  roll  builds  up, 
the  bearings,  together  with  the  core  shaft  C,  rise  and  pull  on  the 
tail  end  of  chains  L ;  this  turns  the  upper  sprocket  wheel,  and  causes 
arm  M  to  move  to  the  right.  Weight  U'  also  moves  to  the  right, 
and  as  the  roll  gets  larger,  the  pull  exerted  by  U'  gets  stronger, 
until  the  maximum  effect  is  reached  when  arm  M  is  in  the  dotted 
position  M'  and  the  roll  is  in  the  position  r.  A  grooved  wheel 
and  cable  may  be  used  in  place  of  arms  similar  to  M. 

310.  In  another  type  of  winder,  compensation  for  the  weight 
of  the  roll  is  secured  by  a  set  of  weights  on  straight  arms  (like 
spokes  of  a  wheel)  that  stand  out  from  the  shaft  U.  Changes 
can  be  made  in  the  angular  setting  of  the  arms,  the  sizes  of  the 
weights,  and  their  distance  from  the  shaft.  Usually,  one  weight 
is  set  to  put  a  little  extra  weight  on  the  core  shaft  when  a  new 
roll  is  started,  and  the  rest  of  the  weights  are  vertical.  As  the 
roll  winds  up,  the  main  weights  revolve,  and  they  gradually 
pull  more  and  more  in  lifting  the  core  shaft. 

Some  makers  of  winders  prefer  to  let  the  roll  build  up  naturally, 
in  which  case,  they  provide  a  large  drum  to  support  the  full 
weight,  and  supply  a  counterpoise  just  for  cores  and  shaft. 

311.  Taking  Out  Finished  Rolls.— When  the  roll  has  been 
wound  to  the  right  size,  the  winder.  Fig.  81,  is  stopped  and  the 
paper  is  broken.  The  operator  turns  hand  wheel  Hi,  which 
turns  shaft  U  by  means  of  the  reducing  gearing  that  is  made  up 
of  gears  Gi  (behind  the  ratchet  wheel).  Go,  Gz,  and  Ga;  and  as 
shaft  U  turns,  it  pulls  up  on  the  left-hand  part  of  chain  L,  lifting 
the  core  shaft  C  and  the  rolls  r  clear  of  the  drums  W  and  W ,  where 
they  are  held  in  that  position  by  the  pawls  Pi  and  Pi-  Planks 
can  be  slid  under  the  rolls,  which  are  then  lowered  and  the  bearings 
opened,  to  release  the  core  shaft.  The  rolls  are  rolled  off  to  a 
platform  or  truck,  or  lifted  off  with  a  compressed-air  or  electric 
hoist,  the  collars  are  loosened,  and  the  core  shaft  is  pulled  out 


202  PAPER-MAKING  MACHINES  §6 

and  placed  on  the  standards  Y,  new  cores  being  slipped  into 
place.  The  rolls  are  then  wrapped  or  are  sent  to  the  finishing 
room.  The  core  shaft  is  put  back  into  the  bearings  and  lowered 
into  position  to  start  a  new  roll. 

The  size  of  the  roll  does  not  necessarily  correspond  to  the  size 
of  the  reel,  but  the  reels  are  generally  changed  so  that  the  rolls 
may  be  wound  without  breaks. 

Hand  wheel  H2  and  pawl  Po  are  used  for  the  rapid  operation  of 
empty  cores  or  small  rolls,  as  when  mending  a  break. 

312.  Handling  Roll  when  Paper  Breaks. — When  a  break 
in  the  paper  occurs,  the  rolls  are  lifted,  and  any  spoiled  paper  is 
removed,  taking  care  to  keep  all  the  rolls  on  the  core  shaft  of  the 
same  diameter.  The  paper  is  torn  square  across,  a  strip  of 
splicing  tissue  is  laid  across  the  rolls,  and  the  end  of  the  new 
strips  is  pulled  taut  and  held  firmly  over  the  adhesive.  A  hot 
flat  iron  (266°F.)  is  passed  over  the  joint,  and  the  loose  end  of  the 
paper  is  creased  and  torn  off.  The  rolls  are  lowered  onto  the 
drums  and  the  winder  is  started; — slowly  at  first,  until  the  joint 
is  wound  into  the  roll; — then  it  is  brought  up  to  speed.  (See 
also  Art.  324.)  In  some  mills,  the  ends  are  stuck  together  with 
flour  paste. 

313.  Angle  between  Paper  Core  and  Winders. — Referring  to 
the  diagram.  Fig.  84,  R  and  S  represent  the  winder  rolls,  and  T 


Fig.  84. 

the  paper  roll  at  the  beginning  of  the  winding.  Drawing  lines 
from  the  center  of  T  to  the  centers  of  R  and  >S,  they  form  the 
angle  A.  As  the  roll  increases  in  diameter,  the  center  of  T 
rises,  and  the  angle  A  decreases;  in  other  words  the  angle  A  is 
continually  varying  with  the  size  of  the  paper  roll.  Under  these 
circumstances,  it  is  evident  that  the  larger  the  angle  A  the  greater 
is  the  grip  between  rolls  R  and  S  and  roll  T.  For  heavy  paper 
or  pulp,  the  angle  A  should  not  be  less  than  115°;  for  lighter 
papers,  say  up  to  30-pound  news,  angles  a  few  degrees  smaller  can 


§6  CALENDERS,  SLITTERS  AND  WINDERS         203 

be  used  successfully.  It  is  an  advantage  to  be  able  to  vary  the 
distance  between  the  centers  of  the  winder  rolls,  so  as  to  have 
some  control  of  the  gripping  effect  of  the  revolving  drums,  as 
applied  to  the  surface  of  the  paper  roll. 

314.  Grooved  Rolls. — It  happens,  unfortunately,  that  the 
perfect  conditions  required  to  obtain  a  "bulls  eye,"  as  the 
machine  tender  sometimes  calls  a  perfect  winder  roll,  are  not 
easily  attained.  A  winder  that  works  well  with  one  paper  and 
has  no  adjusting  devices,  may  not  work  well  with  another  paper. 
Often  a  grooved  roll,  the  grooves  being  parallel  to  the  axis  of  the 
roll  or  else  so  inclined  as  to  form  an  angle  pointing  in  the  direction 
the  roll  is  travelling,  will  enable  the  paper  maker  to  obtain 
better  winder  rolls  than  with  the  ordinary  ungrooved  rolls.  The 
grooved  roll  tends  to  offset  the  bad  results  due  to  faulty  design  in 
spacing,  in  diameter,  and  in  crowning  of  the  winder  rolls;  and  when 
a  winder  is  to  be  designed  for  universal  service,  a  grooved  roll  is  an 
advantage.  The  grooves  further  assist  in  separating  the  rolls 
and  in  preventing  interwinding.  It  may  here  be  mentioned 
that  winder  rolls  should  be  crowned  just  as  carefully  as  lower 
press  rolls.  A  clever  arrangement  is  used  in  a  Canadian  mill 
to  get  hard  rolls  of  paper.  Both  winder  rolls  are  driven  by 
separate  belts;  when  a  new  paper  roll  is  started,  roll  W, 
Fig.  81,  is  driven  slightly  faster  than  roll  W,  so  as  to  obtain 
enough  friction  on  the  paper  to  get  a  tight  center.  As  the  roll 
builds  up,  its  weight  increases  the  friction,  and  the  paper  is 
kept  tight  on  the  roll;  the  belt  driving  W  is  automatically 
slipped  along  a  cone  pulley,  gradually  decreasing  the  speed  of 
W  until  it  has  the  same  speed  as  roll  W. 

315.  Other  Types  of  Winders. — The  details  and  operation  of 
the  winder  shown  in  Fig.  81,  are  typical  of  allwinders;  but  the 
different  makes  exhibit  various  characteristics.  One  make,  for 
instance,  has  drums  of  unequal  size;  thus,  the  drum  correspond- 
ing to  W  in  Fig.  81  is  28  inches  in  diameter,  while  that  corresponding 
to  W  is  only  12  inches  in  diameter.  The  larger  drum  carries  the 
greater  part  of  the  weight  of  the  roll,  and  its  size  gives  it  greater 
contact  with  the  paper.  The  drums  are  so  grooved  that  the 
rolls  do  not  run  together,  and  the  small  drum  is  protected  by  a 
guard,  which  is  automatically  kept  at  a  constant  distance  from 
the  paper.  The  guard  is  desirable,  because  the  paper  is  brought 
up  behind  the  second  roll,  not  between  them,  as  in  Fig.  81,  and 


204  PAPER-MAKING  MACHINES  §6 

the  drums  therefore  turn  in  a  direction  opposite  to  that  indicated 
on  Fig.  81.  (If  the  drums  in  Fig.  81  were  to  turn  in  the  opposite 
direction,  there  would  be  danger  of  catching  the  fingers  or  the 
clothing  between  drum  W  and  the  paper  roll  r.  Rolls  turning 
in  this  manner  would  be  called  "in  running"  rolls.)  Instead 
of  the  chain  lift  on  the  core-shaft  bearings,  the  winder-shaft 
bearings  are  attached  to  the  lower  end  of  racks,  which  mesh 
with  pinions  that  are  operated  simultaneously  by  worm  gears. 
The  racks  run  through  rigid  guides,  to  take  up  the  end  thrust 
on  the  winder  shaft.  On  these  winders,  ball  bearings  are 
extensively    used. 

316.  Four-Roll  Winder. — An  important  development  of  this 
type  of  winder  is  the  use  of  4  drums  and  several  core  shafts. 
This  prevents  entirely  the  interwinding  of  rolls,  since  no  two 
rolls  are  adjacent.  The  shafts  are  short,  and  they  are  confined 
to  the  outside  ends,  to  take  care  of  the  side  thrust.  A  great 
advantage  of  this  design  is  that,  if  there  be  a  streak  or  defects  in 
one  part  of  the  sheet,  the  defective  paper  may  be  cut  off  from  one 
roll,  something  that  is  impossible  with  a  two-drum  winder,  since 
the  paper  on  one  roll  would  not  be  pressed  against  the  winder, 
in  that  case,  and  a  poor  roll  would  result. 

317.  Compensating  Winder.— On  paper  machines,  the  com- 
pensating winder  has  largely  been  supplanted  by  the  constant- 
speed  type.  The  former  (older)  type  is  still  common  on  board 
machines,  and  will  be  fully  described  in  that  connection.  The 
main  principle  that  governs  its  design  is  to  have  a  set  of  core 
shafts,  usually  2  or  4,  driven  through  a  set  of  spur  and  differential 
gearing.  The  difficulty  attending  its  operation  is  that  the  core 
shafts  run  at  constant  speed;  thus,  as  the  rolls  grow  larger,  the 
speed  of  the  paper  increases  until  it  becomes  very  great,  which 
often  causes  trouble  in  winding.  It  is  also  difficult  to  have  the 
rolls  uniformly  solid. 

318.  The  Cutter. — It  has  been  stated  that  on  high-grade, 
tub-sized,  and  air-dried  writing  papers,  it  is  customary  to  cut 
the  paper  into  sheets  just  after  passing  through  the  size  tub. 
With  papers  that  are  dried  and,  as  usual,  calendered  on  the 
paper  machine,  the  cutting  may  also  be  done  in  the  machine 
room,  as  the  paper  comes  from  the  slitters.  This  practice 
eliminates  the  winder  and  the  troubles  incident  to  its  operation. 
Where  the  paper  is  to  be  sized  in  the  full  width  of  the  sheet  and 


§6  CALENDERS,  SLITTERS  AND  WINDERS         205 

cut  in  the  finishing  room,  the  paper  is  dried  by  an  auxiUary  nest 
of  5  or  6  drjdng  cyhnders,  or  by  one  of  the  systems  of  air-drying 
described  in  Tub  Sizing  and  Finishing  Operations,  Vol.  V. 

The  advantageous  use  of  a  cutter  here  depends  on  the  weight  of 
the  paper  and  the  length  of  the  sheet  to  be  cut.  The  cutter 
knife  can  make  only  a  certain  number  of  revolutions  per  minute 
effectively  and  efficienth',  and  it  can  operate  faster  on  relatively 
thick  than  on  thin  papers,  since  the  sheets  are  then  delivered 
and  piled  better,  as  they  are  cut.  The  longer  the  sheet  the  faster 
is  the  paper  taken  from  the  reel,  and,  hence,  the  greater  is  the 
possible  speed  of  the  machine.  If  the  cutter  is  making  70  clips 
per  minute  on  24"  X  36"  sheets,  the  long  side  being  with  the 

grain,  the  possible  machine  speed  is  — t^ —  =  210  ft.  per  min., 

which  would  be  a  fair  speed  on  heavy,  high-grade  book  paper. 
The  cutter,  which  is  combined  with  an  automatic  piling  device, 
or  layboj'",  is  fully  described  in  Vol.  V,  in  the  Section  on  Tub 
Sizing  and  Finishing  Operations. 

WINDING  TROUBLES 

319.  Variable  Tension. — At  the  start  of  the  winding,  the 
tension,  or  pull,  on  the  paper  is  light,  and  it  is  adjusted  by  the 
brake  band  on  the  reel  or  unwinding  stand.  As  the  winding 
speed  increases,  the  tension  increases  gradually,  until  the  paper 
is  winding  tight  and  hard.  It  is  very  important  to  get  a  good 
hard  center;  otherwise,  when  the  outside  gets  hard,  as  the  roll 
builds  up,  there  is  almost  a  certainty  of  trouble  with  slipped 
rolls.  With  compensating  winders,  the  speed  becomes  terrific 
as  the  end  of  the  roll  approaches;  and  after  the  half-way  point, 
say  about  two-thirds  of  the  finished  diameter,  it  is  necessary  to 
gradually  reduce  the  tension  of  the  brake  bands,  and,  in  some 
cases,  even  to  let  the  reel  run  loose. 

320.  Wrinkles. — Wrinkles  may  originate  at  the  reels  or  at  the 
winder.  It  is  easier  to  prevent  a  wrinkle  than  to  remove  it; 
but  it  is  sometimes  impossible  to  do  either,  if  the  fault  is  with  the 
paper  before  it  goes  to  the  reel.  A  good  roll  at  the  reel  will 
almost  invariably  run  well  on  the  winder.  The  only  remedy 
for  a  wrinkle  is  to  adjust  roll  B,  Fig.  81,  in  such  a  manner  as  to 
get  the  proper  tension  the  full  width  of  the  sheet.  If  the  paper 
be  slack  on  one  edge,  the  corresponding  end  of  roll  B  is  lowered. 


206  PAPER-MAKING  MACHINES  §6 

If  a  wrinkle  start,  the  end  of  B  toward  the  head  of  the  wrinkle  is 
raised.  In  some  cases,  instead  of  moving  roll  B,  one  of  the 
bearings  on  the  reel,  or  unwinding  stand,  is  movable,  and  this 
may  be  adjusted. 

321.  Curled  Edges. — With  compensating  winders,  one  edge 
of  the  roll  may  display  a  tendency  to  curl  and  to  run  higher  than 
the  body  of  the  roll ;  in  time,  such  an  edge  will  crack.  The  trouble 
is  that  the  slitters  are  dull,  or  they  run  too  slowly,  or  the  upper 
slitter  is  so  set  that  it  overlaps  too  much  on  the  lower  slitter. 
The  temporary  remedy  is  to  lean  a  board  or  plank  against  the 
high  edge,  thus  retarding  the  increase  in  diameter  of  the  roll  at 
this  point.  Curled  edges  are  sometimes  caused  by  defective 
conditions  at  the  dryers. 

322.  Slipped  Rolls. — The  slipped  roll  is  the  dread  of  the 
winder  man.  When  a  roll  is  wound  loose  at  the  center,  and  is 
thus  harder  on  the  outside,  it  is  likely  to  slip  sidewise;  or  a 
portion  of  the  roll  may  slide  out,  especially  if  one  side  of  the  roll 
be  softer  than  the  other  by  reason  of  uneven  thickness  of  the 
paper.  The  usual  remedy  is  to  attach  a  clamp  on  the  core  shaft, 
to  hold  the  center  of  the  roll  in  place.  It  is  best  to  bolt  the 
clamps  fast  when  the  machine  is  stopped;  but  the  two  parts  are 
sometimes  fastened  together  loosely  around  the  shaft,  slipped 
into  position,  and  held  there  by  winding  a  cord  around  the  shaft 
and  against  the  roll  clamp.  This  is  dangerous,  even  when  the 
winder  is  running  slowly,  and  it  should  never  be  attempted  when 
the  winder  is  running  at  high  speed.  This  trouble  is  more  often 
experienced  with  compensating  winders. 

323.  Roll  Slips  on  Reel. — Trouble  is  also  caused  by  the 
slipping  of  the  roll  on  the  reel.  When  this  occurs,  a  stick  should 
be  nailed  on  the  reel,  to  check  it,  if  it  has  not  already  been  done. 
This  may  make  a  dent  in  the  edge,  which  may  cause  the  paper 
to  break  on  the  winder.  The  chief  difficulty  is  this:  the  slitters 
have  been  set  to  cut  a  shaving  f  inch  to  1|  inches  wide  from  either 
edge  of  the  paper,  |  inch  being  about  the  smallest  that  can  be 
handled;  hence,  if  a  roll  slips  on  the  reel,  it  may  cause  a  very  wide 
shaving  on  one  side  and  a  very  narrow  shaving,  or  none  at  all,  on 
the  other  side,  even  leaving  a  rough  edge  on  the  sheet  on  that  side. 
Fortunately,  the  reeling-stand,  or  unwinding-stand,  bearings  are 
adjustable  endwise,  to  take  care  of  just  such  cases.  If  for  any 
reason,  the  movement  of  the  bearings  will  not  make  up  for  the 


§6  CALENDERS,  SLITTERS  AND  WINDERS         207 

slip,  it  may  be  possible  to  slide  the  paper  on  the  drum  by  bump- 
ing the  end  of  the  drum  shaft  with  a  piece  of  shafting  or  the  like, 
much  as  one  would  drive  the  head  on  a  hammer  by  hitting  the 
other  end  of  the  handle.  If  these  remedies  do  not  work,  let  the 
paper  run  through,  and  then  cut  the  poor  paper  from  the  outside 
of  the  roll  or  sort  it  out  in  the  finishing  room. 

The  matter  of  shavings  must  again  be  considered  when, 
perchance,  the  shaving  winds  up  on  the  roll;  this  is  sure  to  annoy 
the  printer  or  the  supercalender  man.  If  the  shaving  runs  over, 
adjust  the  guard  on  the  edge  of  the  sheet,  and  look  to  the  width 
of  the  paper.  Sometimes  the  stock  gets  shorter  or  slower,  and 
shrinks  more  on  passing  through  the  machine.  In  this  case, 
pull  out  the  deckles  or  make  the  stock  more  free.  The  lighter 
the  sheet  the  wider  must  be  the  shaving. 

324.  Breaks  in  the  Paper. — Another  source  of  worry  to  those 
who  receive  the  rolls  is  the  matter  of  breaks.  If  the  paper  is  to 
be  supercalendered  or  cut  to  sheet  length,  the  breaks  are  not 
usually  spliced;  but  if  it  go  to  the  printer,  the  two  ends  are  joined 
with  splicing  tissue,  or  by  pasting,  as  was  briefly  described  in 
Art.  312.  The  entire  process  is  fully  discussed  by  E.  P.  Cameron 
in  the  Pulp  and  Paper  Magazine  of  Canada  for  Oct.  2,  1919.  As 
soon  as  a  break  is  repaired,  it  should  be  "flagged,"  by  putting  a 
piece  of  stiff  colored  paper  into  the  roll,  allowing  it  to  stick  out  at 
the  side;  this  is  a  warning  to  the  press  man. 

325.  Important. — Perhaps  the  most  important  point  in  run- 
ning a  winder  is  to  see  that  the  slitters  are  set  right.  The  best 
way  of  accomplishing  this  is  for  two  or  more  members  of  the 
crew  to  read  the  machine  order,  and  for  each  to  measure  the  rolls 
accurately. 

Note. — The  description  of  the  paper  machine  is  continued  in 
Vol.  V,  Section  1.  Part  1  of  this  section  will  treat  of  cylinders 
and  special  machines,  etc.  Part  2  will  treat  of  the  Paper  Machine 
drives,  including  the  usual  mechanical  driving  arrangements 
and  the  latest  developments  of  the  electric  drive. 


PAPER-MAKING 
MACHINES 

(PART  4) 


EXAMINATION  QUESTIONS 

(1)  (o)  What  is  the  purpose  of  the  spring  roll  at  the  calender 
end  of  the  dryer  part?  (6)  Can  you  devise  another  arrangement 
to  accomplish  the  same  purpose? 

(2)  (a)  Why  is  the  calender  dangerous?  (6)  How  may 
accidents  be  avoided? 

(3)  Explain  the  purpose  and  action  of  the  calender. 

(4)  Describe  a  calender  stack,  and  state  the  course  of  the 
paper  through  it. 

(5)  (a)  What  is  the  effect,  as  regards  calendering,  of  too 
much,  too  little,  or  just  enough  moisture  in  the  paper?  (6) 
How  can  the  moisture  content  be  controlled? 

(6)  Mention  some  calender  troubles,  their  causes,  and  their 
remedies. 

(7)  (a)  Why  is  the  bottom  calender  roll  crowned?  (6)  Give 
your  own  ideas  as  to  the  reasons  for  the  various  sizes  and  crown- 
ing of  the  different  rolls  in  the  calender  stack. 

(8)  Explain  what  effects  are  produced  on  the  paper  by 
improper  crowning. 

(9)  (a)  Why  is  a  reel  necessary?  (6)  What  are  the  principal 
types? 

(10)  Describe  what  you  consider  to  be  the  best  type  of  reel, 
and  explain  why  you  consider  it  superior  to  any  of  the  other 
types  illustrated. 

(11)  How  is  the  tension  of  the  paper  controlled  during 
winding? 

(12)  Explain  the  principle  governing  the  operation  of  each 
of  two  types  of  slitters. 

(13)  Describe  the  two-drum  winder. 

§6  209 


210  PAPER-MAKING  MACHINES  §6 

(14)  How  does  the  four-drum  winder  differ  from  the  two- 
drum  type,  and  why  are  both  better  for  most  purposes  than 
the  compensating  shaft-driven  winder? 

(15)  (a)  How  is  the  roll  started  on  a  two-drum  winder?  (6) 
What  is  meant  by  in-running  rolls? 

(16)  (a)  What  causes  a  slipped  roll?  How  is  it  checked  (6) 
on  the  reel?  (c)  on  the  winder? 

(17)  What  is  done  in  case  of  a  break  in  the  paper  being  wound? 


INDEX 


Note. — The  paging  begins  with    1   in  each    Section,  and   each   section   has   its   number 

printed    on    the    inside    edge   of  the  headhne    of    each  page.     To    find    a    reference,    as 

"Alum,    Acid,    §4,    p27,"    glance    through    the    volume  until    §4    is   found,   and   then   find 
page  27. 


A 


Accidents,  Prevention  of,  §6,  pi47 
Acid  alum  (De/.),  §4,  p27 
Acid  dyestuflfs,  §5,  p7 

Action  of,  §5,  p35 
Agalite,  Properties  and  uses  of,  §4,  plO 
Agave,  Characteristics  of,  §1,  p40 
Air  pumps,  §6,  pl64 
Air,  Saturated,  §6,  pl74 
Air    supply    for    dryers,     Calculating    the, 

§6,  pl73 
Alkalinity     of     fillers.     Determination     of, 

§4,  p20 
Alum  (Z)e/.),  §4,  p26 
Acid,  §4,  p27 

Action  of,  on  dyestuffs,  §5,  p36 
Adding,  to  beater,  §4,  p38 
Amount  of,  in  sizing,  §4,  p39 
Analyses  of,  §4,  p27 
Commercial,  how  made,  §4,  p26 
Iron-free,  how  made,  §4,  p26 
Paper-maker's,  §4,  p26 
Alum  and  rosin  size.   Reaction  of,    §4,  p28 
Alums,  Commercial,  Uniformity  of,  §4,  p27 
Aniline     dyes.     Classification     of,     §5,     p6 

Reasons  for  using,  §5,  p5 
Aniline  dyestuff,  first.  Discovery  of,   §5,  p2 
Aniline    dyestuffs.    Separation    of,     §5,    p20 
Separation     of,     into     groups,       §5, 

pp20,  22 
Source  of,  §5,  p3 
Aniline  pigments.  Separation  of,  §5,  p20 

sulphate.    Use   of,  for  testing  paper, 
§2,  pl2 
Animal  size  (Def.),  §4,  p23 
Apron  (De/.),  §6,  p42 
Care  of,  §6,  p81 
Putting  on  the,  §6,  p43 
Apron  board,  §6,  p42 
Asbestine,  Use  of,  as  filler,  §4,  pi  I 
Automatic  regulator,  §6,  pl4 

stuff  box,  §6,  pl4 
Azo  dyes  (Def.),  §5,  pl2 


B 


Back-fall  (Def.),  §3,  p6 

Back  side  of  paper  machine  (Def.),   §6,   p60 

Back  water  (Def.),  §5,  p8 


Baffles,  in  flow  box,  §6,  p42 
Bagasse,  or  begass,  §1,  p46 

Preparing  of,  for  paper  making,  §1,  p46 
Bamboo,  Characteristics  of,  §1,  po9 

Use  of,  in  paper  making,  §1,  po9 
Bands,    Brake,    for    unreeling    stand,    etc., 

§6,  pl95 
Barclay,  H.,  §6,  p37 

Barium  sulphate.   Use  of,   as  filler,    §4,  pl2 
Barytes,  Use  of,  as  filler,  §4,  pl2 
Basic  alumina  (Def.),  §4,  p27 

Action' of,  §5,  p3.5 
Beater,  Adding  alum  to,  §4,  p38 

Adding  coloring  matters  to,  §3,  p42 

Adjustable  doctor  for,  §3,  p33 

Bird  attachment  for,  §3,  p31 

Chemical  action  of,  §3,  p49 

Composition  of  furnish  for,  §3,  p37 

Emerson,  §3,  pl7 

Equipment  for  coloring  in,  §5,  p34 

Furnishing  size  to,  §4,  p38 

Griley-Unkle  attachment  for,  §3,  p31 

Hollander,  §3,  p9 

Home,  §3,  p9 

Marx,  §3,  pl4 

Matching  shades  in,  §5,  p41 

Mechanical  action  of,  §3,  p47 

Miller  duplex,  §3,  pl3 

Niagara,  §3,  pi 6 

Rabus,  §3,  plo 

Shartle  attachment  for,  §3,  p30 

Shlick's    beater-hood    attachment    for, 
§3,  p33 

Sizing  in,  §3,  p41 

Stobie,  §3,  pl7 

Umpherston,  §3,  pll 
Beater  drag,  §3,  p61 

roll  and  bars,  §3,  p7 
Beater-roll  counterpoise,  §3,  p32 

regulator,  Wallace-Masson,  §3,  p32 
Beater-room  equipment,  §3,  p22 

layout,  §3,  p34 
Beaters,  Care  of,  §3,  pl9 

Cleanliness  of,  §3,  p20 

Swelling  of  wood  of,  §3,  p21 

Use  of  paint  on,  §3,  p21 
Beating  (.Def.),  §3,  p2 

Circulation  theory  of,  §3,  p52 

Control     of,     by     measuring     freeness, 
§3,  p63 


211 


212 


INDEX 


Beating,  Fibrage  theory  of,  §3,  pol 
History  of.  §3,  p2 
How  conducted,  §3,  p-49 
Recording  changes  in  stock  by,  §3,  p61 
Results  obtained  by,  §3,  p49 
Theory  of,  §3,  p46 
Two  ways  of  controlling,  §3,  poo 
Viscosity  theory  of,  §3,  p54 
Beating  and  refining.  Distinction  between, 

§3.  pi 
Bed-plate  of  beater,  §3,  p8 
Belts  and  felts,  Analogy  between,  §6,  pl26 
Bench  system  of  sorting  waste  paper,  §2,  plO 
Bibliography    (beaters    and    beating),     §3, 

PP71-77 
Bird  attachment  for  beater,  §3,  p31 
Bleach,  Amount  of,  needed  for  rag  stock, 

§1,  p34 
Bleaching  esparto  stock,  §1,  p52 
jute,  §1,  p43 

manila-rope  stock,  §1,  p41 
process  for  rag  stock,  §1,  p32 
straw  stock,  §1,  po7 
Bleaching,  Theory  of,  §1,  p30 

waste-paper  stock  from  special  papers, 
§2,  p65 
in  washing  engine,  §2,  p64 
Consumption  of  bleach  in,    §2,   p64 
Use    of    wet    machine    in,     §2,    p66 
Variation  in  color  of  bleached  pulp, 
§2,  p6o 
Bleach'  liquor,  Preparing,  for  rag  stock,  §1, 

p31 
Blotting  papers,  Coloring  of,  §5,  poO 
Blowout  (in  separatmg  dyestuffs),   §o,  p21 
Board,  Apron,  §6,  p42 

Guard,  §6,  p67 
Boards,  coarse.  Furnish  for,  §3,  p4o 

Use  of  waste  papers  for  making,  §2,  p57 
Boiler,  Cylindrical  rotary,  §1,  p20 

Spherical  (globe)  rotary,  §1,  p22 
Bond  papers.  Sizing  of,  §4,  p46 
Bonds,  high-grade  rag,  Furnish  for,  §3,  p43 
Book  papers.  Furnish  for,  §3,  p44 

Sizing  of,  §4,  p4o 
Borax,  Action  of,  on  dyestuffs,  §5,  p36 
Box,  A  simple  regulating,  §6,  pl3 
flow,  New  design  of,  §6,  p44 
Head,  breast-roll  feed,  or  flow,  §6,  p41 
regulating.  Functions  of,  §6,  pl2 
Boxes,  Felt  suction,  §6,  pllS 
Save-all,  §6,  pl6 

suction.    Braking    effects    of,    §6,    p91 
suction.  Purpose  of,  §6,  p56 
Brake    bands    for    unreeling    stands,    etc., 

§6,  pl9o 
Breaks,  at  calendar.   Causes  for,    §6,  pl84 
during  winding,  §6,  p207 
in  paper,  Flagging,  §6,  p207 
Breast  roll,  §6,  po3 


Breast-roll  details,  §6,  p53 

feed  box,  §6,  p41 
Broke  (Z)e/.),  §3,  pl7 

Pulping,  §3,  p37 
Broomed  (Z>e/.).  §3,  p47 
Bulk  (.Def.),  §6,  pl83 
Bulking,  uneven,  Corrections  for,   §6,  plS3 


Calender  coloring,  §5,  p46 

Apparatus  used  in,  §5,  p47 
Efficiency  of,  §5,  p48 
Formulas  for,  §5,  p47 
Low  cost  of,  §5,  p46 
with    basic    and    direct    dyestuffs, 
§5,  p47 
Calender  doctors,  §6,  pl82 
stack,  §6,  pp3,  180 

troubles.  Causes  of  some,  §6,  pl84 
Calendering,  §6,  p3 
Calenders,  Moisture  in  paper  at,   §6,  pl82 

Purpose  of,  §6,  pl81 
Canary  paste  {Def.),  §5,  plO 
Carbon  black  {Def.),  §5,  pll 
Carrier    system    of   sorting    waste    papers, 

§2,  plo 
Casein,  Use  of  in  sizing,  §4,  p42 
Caustic  soda.   Cooking  rags  with,    §1,  p26 
Influence  of,  on  yield  of  straw  cellu- 
lose, §1,  p58 
Centrifuge,    Use   of,   to   de-water   samples, 

§3,  p64 
Chalk,  Use  of,  as  filler,  §4,  pl2 
Chest,  Stuff,  §6,  po 

Capacity  and  size  of,  §6,  p7 
Care  of,  §6,  p8 
Horizontal,  §6,  p8 
China  clay,  §4,  p4 
Chlorine,  liquid.  Use  of,  §1,  p32 
Chrome  yellows  {Def.),  §5,  plO 
Circulation  theory  of  beating,  §3,  po2 
Claflin  refiner,  §3,  p69 
Clay,  how  obtained,  §4,  p4 
Impurities  in,  §4,  p4 
Methods  of  handling,  §4,  p6 
Properties  of,  §4,  po 
Quantity  of,  used  in  paper,  §4,  p6 
Clothing  {Def.),  §6,  p53 
Coal  tar.  Source  of,  §5,  pll 
Coated  papers,  Sizing  of,  §4,  p45 
Colophony  (rosin),  §4,  p24 
Color,  Effect  of  sizing  on,  §4,  p43 

Fast,  §5.  po 
Color  formulas,  §5,  p25 

Building  up,  §o,  p40 
Colored    print    {Def.),    §2,  p27 
Coloring,  Combination  method  of,  §o,  p4S 
Equipment  for,  in  beater,  §5,  p34 
Tub  method  of,  §5,  p49 


INDEX 


213 


Coloring,  Calender,  §5,  p-t6 
Apparatus  for,  §5,  p47 
Efficiency  of,  §5,  p48 
Formulas  for,  §5,  p47 
Low  cost  of,  §5,  p46 
with  basic  and  direct  dyestuffs,  §5,p47 
Coloring  blotting  papers,  §5,  p50 
crepe  tissues,  §o,  pol 
duplex  papers,  §5,  pol 
oatmeal,    mottled,    or   granite   papers, 

§5,  p49 
paper,  Methods  of,  §5,  p  31 
papers.  History  of,  §5,  p2 
papers,  Importance  of,  §5,  pi 
parchment     and     vulcanized      papers, 

§5,  p52 
to  produce  cloudy  effects,  §5,  pol 
unsized  papers,  §5,  p36 
Color  of  fillers,  §4,  pl7 

Color  matches,  Use  of  laboratory,   §5,  p41 
Color  room,  Equipment  of,  §5,  p32 

Necessity  for  a,  §5,  p32 
Color-solution  storage  tanks,   §5,  pl3 
Color  value  of  dyestuffs,  §5,  p31 

tests  should  be  comparable,  §5,  p29 
Colors,  Vat,  §5,  p8 

Manufacture  of,  §5,  pl3 
Concentration  (i>e/.),  §3,  p46 

Most  efficient,  §3,  p52 
Consistency  (De/.),  §3,  p46 

Control  of,  at  Jordan,  §3,  p59 

Control   of,   by  setting  beater  roll,  §3, 

p60 
Control  of,  by  watt  meter,  §3,  p60 
indicator,  §3,  p58 
Regulating  the,  §6,  pl4 
Regulation  of,  §6,pl2 
regulator,  §3,  pl2 
Constant-speed  winder,  §6,  p201 
Control  of  beating,  §3,  poo 

of  density,  §3,  poo 
Controlling  beating  by  measuring  freeness, 

§3,  p63 
Controlling  consistency  at  Jordan,  §3,  po9 
by  setting  of  roll,  §3,  p60 
by  watt  meter,  §3,  p60 
Containers  for  sorted  waste  papers,  §2,  pl4 
Converting  rags  into  paper,  Early  methods 

of,  §1,  p2 
Cooking  cotton-seed  hulls,  §1,  p45 
Cooking  engine,  Operation  of,  §2,  p46 
Cooking-engine  process,  Advantages  of,  §2, 

p47 
Cooking  engine.  Use  of,  for  waste  papers, 

§2,  p46 
Cooking  jute,  §1,  p43 

linens,  §1,  p2.5 
Cooking  liquor,  §1,  plS 

Amount  and  strength  of.  for  rotary- 
boiler  process,   §2,  p40 


Cooking  liquor,  for  esparto,  §1,  poO 
for  straw,  §1,  po6 
for  waste  papers,  §2,  p30 
for  waste  papers.  Preparation  of,  §2, 

p31 
Losses  in  recovering  chemicals  in  §2, 

p36 
Recovering  chemicals  in,  §2,  p35 
Cooking  manila  rope,  §1,  p41 
old  whites,  §1,  p24 
practice.  Variations  in,  §1,  p26 
process  for  straw,  §1,  p56 
rags  with  caustic  soda,  §1,  p26 
rags  with  lime,  §1,  p23 
rosin,  §4,  p30 

tank  for  waste  papers,  §2,  p29 
Cooking  waste  papers  bj'  rotary-boiler  proc- 
ess, §2,  p37 
Furnishing  the  tanks  for,  §2,  p30 
in  open  tanks,  §2,  p28 
Methods  of,  §2,  p28 

reducing  consumption  of  steam  in,  §2, 
p33 
Cooking  white  and  colored  cotton  mixtures, 

§1,  p2o 
Copper  sulphate,  Action  of,  on  dyestuffs,  §5, 

p37 
Cotton,  Analysis  of,  §1,  p4 

Characteristics  of,  §1,  p3 
Cotton-seed  hulls,  Cooking  of,  §1,  p4o 

Preliminary  treatment  of,  §1,  p45 
Use  of,  in  paper  making,  §1,  p44 
Couch  roll,  Handling  of,  §6,  p86 
housings,  §6,  p66 
jacket,  English  felted,  §6,  p91 
jacket.  Shrinking  the,  §6,  p89 
jacket,  Starting  a  new,  §6,  p90 
jackets.  Troubles  with  and  care  of, 

§6,  p90 
jackets,  Use  of,  §6,  p88 
journals,  Lubricating  of,  §6,  pl27 
Putting  new  jacket  on,  §6,  pS7 
Suction,  §5,  p68 
suction.  Suction  in,  §6,  p91 
Couch  rolls.  Driving  the,  §6,  p65 

Purpose  of,  §6,  p64 
Coumarone  resins,  §4,  p42 
Course  of  paper  through  machine,  §6,  p2 
of  paper  through  press  part,  §6,  plOl 
of  press  felts,  §6,  pl03 
of  wire  through  Fourdrinier  part,  §6,  p3S 
Crepe  tissues.  Coloring  of,  §5,  pol 
Crown  (Def.),  §6,  p52 

Crown  filler,  Properties  and  uses  of  §4,  pll 
Crown  of  rolls,  §6,  po2 

Crowning,    Determining    accuracy    of,    §6, 
pl8o 
of  smoothing  rolls,   §6,  pl43 
Crudes,  §5,  pl2 

Source  of,  §5,  pll 


214 


INDEX 


Crushed  fibers  (De/.),  §3,  p47 

paper  (Def.),  §6,  p56 
Crushing,  Cause  of  and  remedy  for,  §6,  p65 
Curb  for  beater  roll,  §3,  p8 
Curled  edges.  Cause  of,  §6,  p205 
Cut  squirt.  Use  of,  §6,  p39 
Cutter,  Score,  §6,  pl99 
Cutter,  The,  §6,  p204 
Cutters  for  waste-paper  stock,  §2,  p21 

for  rags,  §1,  pl3 
Cutting  rags,  §1,  pl3 


D 


Dandy  roll  (Def.),  §6,  p61 
Dandy  rolls.  Defects  caused  by,  §6,  p63 
Putting  on  and  removing,  §6,  p63 
Size  and  position  of,  §6,  p62 
Deckle  frame,  §6,  p46 
pulleys,  §6,  p48 
Shakeless,  §6,  p48 
strap,  §6,  p48 
The,  §6,  pp46-49 
De-inking  waste-paper  stock  by  mechanical 

treatment,  §2,  p49 
Density  (Def.),  §3,  p46 
Control  of,  §3,  poo 
of  stock,  Influence  of,  in  coloring,  §5, 
p39 
De-watering  devices,  §6,  p99 
Dew  point  {Def.),  §6,  pl74 
Diazo  dyes  {Def.),  §5,  pl2 
Diazotization  (Def.),  §5,  pl2 
Dickinson,  John,  patents  cylinder  machine, 

§6,  p37 
Didot,  purchases  Robert's  patent,  §6,  p35 
Diluting  size,  Systems  of,  §4,  p35 
Dippers   and   siphons,    Comparison   of,    §6, 

pl57 
Dippers,  Use  of,  §6,  pl55 
Dip  test  for  dyes,  §5,  p24 
Direct  dyestuffs,  §5,  p7 

Action  of,  §5,  p35 
Disks,  Slitter,  §6,  pl97 
Doctor  (Def.),  §6.  pl44 

Adjustable,  for  beater,  §3,  p33 

Calender,  §6,  pl82 

Vibrating,   §6,  pUO 

Donkin,  Bryan,  §6,  p35 

Draining  rag  stock,  §1,  p34 

Draw  (Def.),  §6,  pplOo,  137 

Correcting  faulty,  §6,  pl37 
Drive  for  reels  and  winders,  Slip-belt,   §6, 

pl93 
Dry  broke  (Def),  §3,  pl7 
Dry  cooks.  Cause  of,  §2,  p31 
Dryer  felt.  Flapping  of,  §6,  pi67 
Putting  on  a  new,  §6,  pi 65 
rolls,  §6,  p52 
Rule  for  running  of,  §6,  pl66 


Dryer  felts,  Automatic  guide  for,  §6,  pl50 
Automatic  stretcher  for,  §6,  pl51 
Controlling  tension  of,  §6,  pl64 
Course  of,  §6,  pl45 
Starting  the,  §6.  pl66 
Strength  of,  §6,  pl66 
Dryer  part,  Breaks  of  paper  in,  §6,  pl68 
ControlUng  press  end  of,   §6,  pl64 
Operation  of,  §6,  pl59 
what  it  consists  of,  §6,  pl44 
Dryer  section,   dryer  part,   or   dryer   nest 
(Def.),  §6,  pl41 
Two  parts  of,  §6,  pl45 
Dryer    surface    required.    Calculating,     §0, 

pl72 
Dryer  troubles,  §6,  pl47 
Dryers,    Calculating    air    supply    for    the, 
§6,  pl72 
Controlling  steam  supply  to,  automati- 
cally, §6,  pl62 
Course  of  paper  through,  §6,  pl47 
Driving  gear  for,  §6,  pl4S 
Keeping  free  from  water,  air,  grease, 

§6,  pl48 
Necessity  for  free  circulation  of  steam 

in,  §6,  pl60 
Number  of,  required,  §6,  pl71 
Passing    paper    from    last    press    to, 

§6,  pl41 
Purpose  of,  §6,  pl44 
Removing  water  from,  §6,  pi. 55 
Special  considerations  concerning,    §6, 

pl61 
Steam-pressure  controlling  system  for, 

§6,  pl60 
Supplying  air  to,  §6,  pl74 
Water  evaporated  by,  §6,  pl70 
Drying   effects.    Conditions   for   maximum, 

§6,  pl69 
Drying  paper,  Influence  of  ventilation  in, 

§6,  pl70 
Duplex  papers.  Coloring  of,  §5,  p5I 
Dust,    Amount    of,    removed    from    waste 

papers,  §2,  pl8 
Duster,  Fan,  for  waste  papers,  §2,  pl7 
Fan,  or  wing,  §1,  plo 
Railroad,  §1,  pl4 

Railroad,  for  waste  papers,  §2,  pl7 
Dusters  for  waste  papers.   Power  required 

for,  §2,  pl8 
Dusters,  Rag,  §1,  pl4 
Dusting  waste  papers,  §2,  pl7 

after  shredding,  §2,  p24 
Machines  used  for,  §2,  pl7 
Dye  or  dyestuff  (Def.),  §5,  p4 
Dyeing  (Def.),  §5,  p4 

Dyeing,  Preparation  of  stocks  for,   §5,  p23 
Spray,  §5,  pol 
Theories  of,  §5,  pl5 


INDEX 


215 


Dyes,  aniline,  Classification  of,  §5,  p(i 
aniline,  Reasons  for  using,  §5,  po 
Azo  and  diazo,  §5,  pl2 
Dip  test  for,  §5,  p24 
Standard  solutions  for  testing,   §5,  p24 
Three  general  groups  of,  §5,  po 
Trade  names  of,  §5,  p6 
Dyestuff,  Amount  of,  to  use,  §5,  p30 
containers,  §5,  p32 
samples.  Testing  of,  §5,  p22 
Dyestuffs,  Acid,  §.5,  p7 

Action  of  acid,   basic,   and   direct,    §5, 

p35 
Action  on,  of  size,  alum,  soda,  borax, 

etc.,  §5,  p36 
Adding,  in  dry  state,  §5,  p39 
aniline,  Separation  of,  §5,  p20 
aniline.  Source  of,  §5,  p3 
Approximate   methods  of  testing,    §5, 

p24 
Basic,  §5,  p6 

basic,  Standardizing  agents  for,  §5,  pl4 
Color  value  of,  §5,  p31 
Combinations  of,  §5,  p44 
Determining  mixtures  of,  §5,  p21 
Direct,  or  substantive,  §5,  p7 
Dissolving,  §5,  p33 
Distinguishing  letters  of,  §5,  p6 
Effect   of    fillers   on   absorptive   power 

for,  §o,  p29 
Effect  of  heat  on,  §3,  p44 
Handling  of,  in  beater  room,    §5,  p46 
Importance  of  standardizing,    §5,   pl3 
Laboratory     equipment     for     testing, 

§5,  pl6 
Matching,  §5,  p30 
Methods  of  Standardizing,  §5,  pl3 
Mixtures  of,  §5,  pl5 
Reduced  brands  of,  §5,  pl4 
Sulphur,  §5,  p8 
Testing,   for  strength   and  shade,    §5, 

p23 
Testing  of,  in  laboratory,  §5,  plo 
yellow.  Strength  of,  §5,  p26 


E 


Edges,  curled.  Cause  of,  §6,  p20.5 
Electromagnets,  RifHers  with,  §6,  p25 
Elutriation  tests  for  fillers,  §4,  pl8 
Emerson  beater,  §3,  pl7 
EngHsh  reel,  §6,  pl88 

Esparto,    Application    of    sulphate  process 
to,  §1,  p53 

Characteristics  of,  §l,p47 

Cooking  liquor  for,  §l,p50 

Cooking  of,  §1,  pp49-52 

Cooking  operation  for,  §1,  p51 

Digesters  for,  §l,p49 

Dusting  of,  §l,p48 


Esparto,   History  of,   in  paper   making,   §1, 
p46 
Outline  of  process  of  preparing,  §1,  p48 
stock,  Washing  and  bleaching,   §1,  po2 
where  grown,  §1,  p47 
Yield  of  paper  from,  §1,  p53 

Extracted  rosin  {Def.),  §4,  p25 


Fade  (change  of  color),  §5,  po 

Fan  duster  for  waste  papers,  §2,  pl7 

Fan,  or  wing,  duster,  Description  of,  §1,  pl5 

Fast  color  {Def.),  §5,  po 

Fastness,  Varieties  of,  §5,  p26 

to  acids,  §5,  p27 

to  alkali,  §5,  p27 

to  chlorine,  §5,  p28 

to  heat,  §5,  p28 

to  light,  §0,  p26 
Fastness  to  light.  Tests  for,  §5,  p27 
Felt,  dryer.  Flapping  of,  §6,  pl67 

Putting  on  a  new,  §6,  pl65 

Rule  for  running  of,  §6,  pl66 
Felt  marks  {Def.),  §6,  pl20 
Felt,  Passing  paper  from  wire  to,  §6,  p39 
Felt,  press.  Function  of  the,  §6,  pl29 

Guiding  the,  §6,  pl25 

Putting  on  a  new,  §6,  pi  19 

Taking  off  the  old,  §6,  pllS 

Washing  the,  §6,  pl21 

Wetting  the,  §6,  pl20 
Felt  rolls.  Balancing  of,  §6,  pl36 

Construction  and  sizes  of,  §6,  pl36 
Size  of,  §6,  pl04 
Felt  stretchers.  Press,  §6,  pi  14 
suction  boxes,  §6,  pi  13 
whippers,  Press,  §6,  pi  16 
Wrinkles  and  slack  places  in  new,  §6, 
pl26 
Felts  and  belts.  Analogy  between,  §6,  pl26 
Felts,   dryer.   Automatic  stretcher  for,    §6, 
plol 

Controlling  tension  of,  §6,  pl64 

Course  of,  §6,  pl4o 

Starting  the,  §6,  pl66 

Strength  of,  §6,  pl66 
Felts,  General  law  of  travel  of,  §6,  pi 50 

General  rules  for  washing,  §6,  pl21 

Guiding  of,  by  stretch  roll,  §6,  plo4 

Influence  of  tension  on  width  of,    §6, 
pl25 

Pick-up,  §6,  pl28 

Preservation  of,  §6,  pl22 
Felts,  press,  Care  and  life  of,  §6,  pl21 

Course  of,  §6,  pl03 

for  particular  papers,  §6,  pl30 

Length  of,  §0,  pi 27 

Qualities  of,  §6,  pl2S 

Washing,  §6,  pi  17 

Weight  of,  §6,  pl28 


216 


INDEX 


Felts,  Tension  of.  §6,  pl24 

Widening  the,  §6,  pl25 
Fenders  of  paper  machine,  §6,  p60 
Fibers,  Crushed  (De/.),  §3,  p47 

Photomicrographs  of,  §3,  p47 
Fibrage  theory  of  beating,  §3,  pol 
Fibrillse  (De/.),  §3,  p47 
Filler  (Z)e/.),  §3,  p37 

Crown,  §4,  pll 

Pearl,  §4,  pl2 

Retention  of,  §4,  pl3 

When  to  add  the,  §4,  pl6 
Fillers  (2)e/.).  §4,  p2 

Analysis  of,  §4,  pl7 

Classification  of,  §4,  p3 

Color  of,  §4,  pl7 

Comparing  two,  §4,  pl9 

Determination  of  alkalinity  of,  §4,  p20 

Determination  of  fineness  of,  §4,  pl7 

Determination  of  moisture  content  of, 
§4,  pl7 

Effect    of,     on    absorption    power    for 
dyestuffs,  §5,  p29 

Elutriation  tests  for,  §4,  plS 

Photomicrographs  of,  §4,  pp8,  9 

Sampling  of,  §4,  pl7 

Sieve  test  for,  §4,  pl9 

Testing  of,  for  iron,  §4,  p22 

what  they  are  and  why  used,  §4,  p2 
Filling  for  fly-bars  {Def.),  §3,  p7 
Filters,  Save-alls  as,  §6,  p23 
Fineness  of  fillers,  Determmation  of,  §4,  pl7 
Finish,  Effect  of,  on  color,  §5,  p45 

Effect  of  sizing  on,  §4,  p43 

Glazed    or  smooth,   how  obtained,  §6, 
pl43 

Variation  in,  §6,  pl86 
Fixed,  or  mordanted  dye,  §3,  p5 
Flow  box  (Z>e/.),  §6,  p41 

New  design  of,  §6,  p44 
Flow  boxes  with  baflBes,  §6,  p42 
Fly-bars  {Def.),  §3,  p7 
Fourdrinier,  Henry  and  Sealy,  §6,  p35 
Fourdrinier  machine.  The  first,  §6,  p36 

The  first,  in  America,  §6,  p36 
Fourdrinier  Part  {Def.),  §6,  p2 

Course  of  wire  through,  §6,  p38 
Lubrication  of,  §6,  p79 
OutHne  of,  §6,  p39 
Fourdrinier  rolls,  §6,  p52 
Free  stock  {Def.),  §3,  p46 
Front  side  of  paper  machine  {Def.),  §6,  p60 
Froth,  Remedy  for,  §6,  pSo 
Froth  spots.  Cause  of,  §4,  p44 
Furnish  {Def.),  §3,  p37 

for  beater.  Composition  of,  §3,  p37 

for  book  paper,  §3,  p44 

for  coarse  boards,  §3,  p4.5 

for  high-grade  rag  bond,  §3,  p43 

for  mixed  stock,  §3,  p44 


Furnish  for  rotary-boiler  process  for  waste 

papers,  §2,  p40 
Furnish,  Loading  contained  in,  §3,  p41 

Order  of,  §5,  p37 

Relation  of  coloring  to,  §5,  p37 

Usual  order  of,  §3,  p40 
Furnishes,  Mixed,  §5,  p39 


Gamble,  John,  §6,  p35 

Granite  papers,  Coloring  of,  §5,  p49 

Grease-proof  papers.  Sizing  of,  §4,  p47 

Grease  spots.  Removal  of,  §6,  pSO 

Griley-Unkle  attachment  for  beater,  §3,  p31 

Grinding  roll  bars,  §3,  pl9 

Grooved  rolls,  §6,  p203 

Guard  board,  §6,  p67 

Guide,  Automatic,  for  dryer  felts,  §6,  ploO 

wire.  Action  of,  §6,  p80 
Guide  rolls,  §6,  p60 

Auto-swing,  §6,  p80 


H 


Half-stuff  {Def.),  §3,  pp4,  46 

dry  and  semi-dry,  pulping  of,  §3,  p40 
Hard  water,  Effect  of,  on  size,  §4.  p37 
Hardness,  Effect  of  sizing  on,  §4,  p43 
Head  box,  §6,  p41 

Heat,  Effect  of,  on  dyestuffs,  §5,  p44 
Hemp,  Characteristics  of,  §1,  p39 

Use  of,  for  paper  making,  §1,  p39 
Hollander,  Defects  of,  §3,  p9 

Invention  of,  §3,  p3 

Roll-adjusting  mechanism  for,  §3,  p9 
Hollander  tub,  §3,  p5 
Hood  for  beater  roll,  §3,  p8 
Home  beater,  §3,  p9 
Housings,  Couch-roll,  §6,  p66 

Press,  §6,  pl06 
Humidity,  Influence  of,  on  drying,  §6,  pl74 
Hydration  {Def.),  §3,  p47 


I 


Indicator  for  consistency,  §3,  p58 
Intermediates,  Manufacture  of,  §5,  pl2 
Iron-free  alum,  how  made,  §4,  p26 
Iron,  oxide  of.  Use  of,  as  filler,  §4,  pl3 

Testing  fillers  for,  §4,  p22 
Iron  oxide  (pigment),  §5,  plO 


Jacket,  couch-roll,  English  felted,    §6,  p91 
couch-roll,  Shrinking  the,  §6,  p89 
couch-roll.  Starting  a  new,  §6,  p90 
new.  Putting  on  couch  roll,  §6,  p87 

Jackets,  couch-roll.  Use  of,  §6,  p88 

Troubles  with  and  care  of,  §6,  p90 


INDEX 


217 


Jackets,  Preservation  of,  §6,  pl22 
Joint,  Steam,  §6,  pl58 

steam,  Lubricating  the,  §6,  pl59 
Jordan  chest  (Z)e/.),  §3,  p36 

Description  of  the,  §3,  p65 
drive,  §3,  p70 
Origin  of  the,  §3,  p67 
Jute,  Characteristics  of,  §1,  p42 
Cooking  of,  §1,  p43 
Preliminary  treatment  of,  §1,  p43 
Sources  of  supply  of,  §1,  p42 
Use  of,  in  paper  making,  §1,  p42 
Washing  and  bleaching,  §1,  p43 
Yield  of  paper  from,  §1,  p44 


Kaolin,  §4,  p4 

Kier,  Mather,  §1,  p22 

Kinks  in  wire.  Removal  of, 


5,  p81 


Laboratory  equipment  for  testing  dyestuffs, 

§5,  pl6 
Laid  paper  (De/.),  §6,  p62 
Lamp  black  (Z)e/.),  §5,  pll 
Layout   for   bench   sj'stem   of   sorting   old 

papers,  §2,  pll 
Lead  acetate.  Action  of,  on  dyestuffs,  §5,  p37 
Ledger  stock.  Standard  for,  §2,  p6 
Left-hand  machine  (De/.),  §6,  p41 
Lighter-bars  {Def.),  §1,  p27 

for  beater  roll,  §3,  p7  • 
Lime  and  soda  ash,  Use  of  in  cooking  rags, 

§1.  p24 
Lime,  Use  of  in  cooking  rags,  §1,  p23 
Linen,  Characteristics  of,  §1,  p25 
Liquid  chlorine.  Use  of,  §1,  p32 
Liquor,  Cooking,  for  rags,  §1,  pl8 

for  waste  papers,  §2,  p30 
Loading  {Def.),  §3,  p37;  §4,  pi 

contained  in  furnish,  §3,  p41 

Reason  for,  §4,  pi 
Long  stock  {Def.),  §3,  p47 
Lubrication  of  Fourdrinier  part,  §6,  p79 
Lumps,  Soft  and  hard,  §6,  p45 

their  effect  and  prevention,  §6,  p72 


M 


Machine  chest  {Def.),  §3,  p36 
^Machine,  Right-  or  left-hand,  §6,  p41 
Magnetic  roll.  Description  of,  §1,  pl6 
Manila  hemp.  Characteristics  of,  §1,  p40 
Manila  rope,  Cutting  up,  §1,  i>40 
Source  of  supply  of,  §1,  p40 
stock.   Washing   and   bleaching,    §1, 

p41 
Yield  of  paper  from,  §1,  p41 


Marshall  refiner,  §3,  pG9 

Marx  beater,  §3,  pl4 

Matches,  color.  Use  of  laboratory,   §5,  p41 

Matching  dyestuffs,  §5,  p30 

shades,  §5,  p29 

shades  in  beater,  §5,  p41 
Mather  kier,  §1,  p22 
Matrix,  Paper  {Def.),  §4,  p2 
Mauve,  Discovery  of,  §5,  p2 
Mesh  {Def.),  §6,  p94 
Metal  and  rubber  in  rags,  §1,  pl2 
Midfeather  {Def.),  §3,  p5 
Mill  size  {Def.),  §4,  p30 
Miller  duplex  beater,  §3,  pl3 
Mixed  paper  stock,  Standard  for,  §2,  p6 
Mixed  stock.  Furnish  for,  §3,  p44 
Mixing  chest,  §3,  p22 

Mixtures  of  dyestuffs,  Determining,  §5,  p21 
Moisture  content  of  fillers.  Determination 

of,  §4,  pl7 
Moisture,  Determination  of,  in  pulp,  §5,  p23 
Moisture  in  paper  at  calenders,  §6,  pl82 
Mordant  {Def.),  §5,  p5 
Mordanted,  or  fixed  dyes,  §5,  p5 
Mordants,  Use  of,  §5,  p35 
Muss  {Def.),  §1,  pl2 


N 


Neutral  size  {Def.),  §4,  p30 
Newsprint,  Sizing  of,  §4,  p45 
Newsprint  stock.  Standard  for,  §2,  p7 
Niagara  beater,  §3,  pl6 
Nitric  acid.  Use  of,  for  testing  paper,  §2,  pl2 
No.  1  book  and  magazine  stock.  Standard 
for,  §2,  p6 


O 


Oatmeal  papers,  Coloring  of,  §5,  p49 
Ochers  {Def.),  §5,  p9 
Oleo  resin,  §4,  p24 

Open-tank  process  {Def.)  of  cooking  waste 
papers,  §2,  p28 


Palms,  Description  of  the,  §6,  p60 
Paper,  Angle  between  core  of,  and  winders, 
§6,  p202 
breaks  during  winding,  §6,  p207 
Cause  of  breaks  in,  in  dryer  part,  §6, 

pl68 
Course  of,  through  dryers,   §6,  pl47 
through  machine,  §6,  p2 
through  press  part,  §6,  plOl 
from  manila  rope.  Yield  of,  §1,  p41 
how  it  should  be  taken  off  the  Four- 
drinier wire,  §6,  p71 
Moisture  in,  at  calenders,  §G,  pl82 


218 


INDEX 


Paper,  Origin  of,  §1,  pi 

Passing,  from  wet  part  to  press  part, 

§6,  p99 
Passing,  from  wire  to  felt,  §6,  p39 
rolls,  Handling  of,  when  paper  breaks, 

§6,  p202 
sized,  Water  resistance  of,  §4,  p40 
Takiag  out  finished  rolls  of,    §0,  p201 
Testing,  for  mechanical  pulp,  §2,  pl2 
Transferring    the,    from    calenders    to 

reel,  §6,  pl89 
waste.  Classification  of,  §2,  pp4.  7 
waste.  Market  quotations  on,  §2,  p5 
waste,  Methods  of  recovery  of,  §2,  p3 
waste,  Value  of,  §2,  p2 
weight  of.  Uniformity  of,  §6,  pl2 
Wove  and  laid,  §6,  p61 
Paper  machine,  Donkin,  §6,  p36 

Improvements  in  earlier,  §6,  p37 
Increasing  capacity  of,  §6,  p84 
Invented  by  Robert,  §6,  p34 
Origin  of,  §6,  pp34-37 
room  details,  §6,  p5 
Paper-maker's  alum  {Def.),  §4,  p26 
Paper  making.  Origin  of,  §1,  pi 

Use  of  cotton-seed  hulls  in,  §1,  p44 
Use  of  hemp  for,  §1,  p39 
Use  of  jute  in,  §1,  p42 
Paper-making  raw  materials,  §1,  p3 
Paper  roll  slips  on  reel,  §6,  p206 
Paper  rolls,  §6,  pll8 

Improperly  wound,  §6,  pl90 
Paper  sheet.  Changing  width  of,  §6,  p44 
tension,  Controlling  the,  §6,  pl90 
Paper  slips  on  roll,  §6,  p206 
Papers,  Grades  of,  §2,  p4 

particular.  Press  felts  for,  §6,  pl30 
various,  Sizing  of,  §4,  p45 
waste,  Use  of,  §2,  pi 
Papyrus,  Origin  of,  §1,  pi 
Parchment,  Origin  of,  §1,  pi 

papers.  Coloring  of,  §5,  p52 
Paris  black,  §5,  pll 

Pearl    filler.    Properties    and    uses    of,    §4, 
pl2 
hardening,   or  crown  filler,    §4,  pll 
Phloroglucine,    Use   of,    for   testing   paper, 

§2,  pl2 
Pigment  (.Def.),  §5,  p8 
Pigments,  Classification  of  aniline,  §5,  p9 

Separation  of,  §5,  p20 
Pinch  roll,  §6,  pl81 
Pitch,  §4,  p24 

Pitch  (from  crudes),  §5,  pl2 
Pitch  spots.  Removal  of,  §6,  p80 
Pope  refiner,  §3,  p68 
Press  felt.  Care  and  life  of,  §6,  pl21 
Course  of,  §6,  pi 03 
for  particular  papers,  §6,  pl30 
Function  of  the,  §6,  pl29 


Press  felt.  Guiding  the,  §0.  pl2o 
Length  of,  §6,  pl27 
Putting  on  a  new,  §6,  pi  19 
Quahties  of,  §6,  pl28 
rolls,  §6,  p52 
stretchers,  §6,  pi  14 
Taking  off  the  old,  §6,  pi  18 
Washing  the,  §6,  ppll7,  121 
Weight  of,  §6,  pl28 
Wetting  the,  §6,  pl20 
whippers,  §6,  pl03 
Press  housings,  §6,  pl06 
Press  part  (Def.),  §6,  plOl 

of  machine  {Def.),  §6,  p2 
Purpose  and  limitations  of,  §6,  plOl 
Press-roll  details,  §6,  pl09 

journals.  Lubricating  of,  §6,  pl27 
Press  rolls,  §6,  p52 

Amount  of  crown  for,  §6,  pl34 
Construction  of,  §6,  pl31 
Crowning  of,  §6,  pl31 
Pressure  produced  by,  §6,  pl08 
Rubber-covered,  §6,  pl32 
suction.  Construction  and  operation 

of,  §6,  pll2 
suction.  Lining  up,  §6,  pll2 
Troubles  due  to  rubber  covering  on, 

§6,  pl33 
Weights  and  levers  for,  §6,  pl07 
Press,  Size,  §6,  pl76 
Presse-p&te  machine,  §1,  pp48,  53 
Print    {Def),   as   applied   to   waste  papers, 

§2,  pl2 
Prussian  blues  {Def.),  §5,  plO 
Pulp,  Moisture  determination  of,  §5,  p23 

Pulping  frozen,  §3,  p39 
Pulper  for  waste  paper,  §3,  p38 
Pulping  broke,  §3,  p37 
Pulping  engine  for  waste  papers,   §2,  p53 
Pulps,  dry  and  semi-dry,  Pulping  of,  §3,  p40 

Handling  of  slush,  §3,  p40 
Pump,  Duplex  plunger,  §3,  p20 

plunger.    Caution    to    be    observed    in 

operating,  §3,  p28 
Stuff,  §3,  p26 

stuff,  Horsepower  of,  §6,  pll 
stuff,  Plunger,  §6,  p9 
stuff.    Regulating   box   for   feeding,  §3, 

p29 
stuff.  Size  of,  §6,  plO 
stuff.  Work  of,  §6,  pll 
Suction,  §6,  p58 
suction,  Displacement  of,  §6,  p59 


R 


Rabus  beater,  §3,  pl.5 
Rag  Cutters,  §1,  pl3 

dusters,  §1,  pl4 

half-stuff,  §1,  ppl3,  18 


INDEX 


219 


Rags    Boilers  for  cooking,  §1,  pp20-23 
Classification  of,  §1,  pp6-9 
Cooking  liquor  for,  §l,pl8 
Cooking  of,  §l,ppl7-30 
Cooking  with  lime,  §l,p23 
Cooking  with  lime  and  soda  ash,  §1,  p24 
General  specifications  for,  §1,  p6 
Inspection  of,  §1,  pl2 
Loss  in  weight  of,  by  thrashing,  §1,  plO 
mixed,   What  1000  lb.  contains,  §1,  p5 
new.  Source  of,  §1,  p4 
old.  Source  of,  §1,  p4 
Preliminary     thrashing     of,      §1,     p9 
Reason  for  cooking,  §l,pl7 
Reason  for  cutting,  §l,pl3 
Rubber  and  metal  in,  §1,  pl2 
Sorting  of,  §l,plO 

Specifications    by    grades,     §1,    pp6-9 
Transporting    and     handling,     §1,    p5 
Uses  of,  §1,  p5 
washing,  Details  of,  §1,  p29 
washing.  Process  of,  §1,  p29 
Rag-sorting  room.   Equipment  of,    §1,  pl2 
Rag  stock.   Bleaching  process  for,    §1,  p32 
Draining  of ,  §l,p34 
Losses    in    preparation    of,    §1,    p37 
Preparing  bleach  liquor  for,  §1,  p31 
Time    that,    is    in    drainer,    §1,    p3.5 
Use  of  wet  machine  for  dewatering, 
§1,  p35 
Rag  thrasher,  §l,p9 
Rags  in  paper  making.  History  of  use  of, 

§l.pl 
Railroad   duster.    Description   of,    §1,    pl4 

for  waste  papers,  §l,pl7 
Rails,  Shake,  §6,  p46 

Reduced  brands  of  dyestuff  (Def.),  §5,  pl4 
Reel,  English,  §6,  pl88 

Paper  roll  slips  on,  §6,  p206 
revolving,  Four-drum,  §6,  pl87 
Three-drum,  §6,  pl91 
Two-drum  upright,  §6,  pl89 
Reel  drums.  Revolving  the,  §6,  pl93 
Reeling-off  stands,  §6,  pl95 
Reels,  Drive  for,  §6,  pl93 
Refiner,  Claflin,  §3,  p69 
Jordan,  §3,  p65 
Marshall,  §3,  p69 
Pope,  §3,  p68 
Wagg-Jordan,  §3,  p69 
Refining  and  beating,  Distinction  between, 

§3.  pi 
Refining  engines,  Purpose  of,  §3,  p65 
Regulating    box,    for   feeding  stuff  pumps, 
§3,  p29 
Functions  of,  §6,  pl2 
Simple,  §6,  pl3 
Regulation,     Conditions     governing     auto- 
matic, §6,  pl3 
Regulator,  Automatic,  §6,  pl4 


Regulator  for  consistency,  {3,  p56 

Resins,  Coumarone  and  synthetic,   §4,  p42 

Retention  (.Def.),  §4,  pl3 

To  calculate  per  cent  of,  §4,  pl3 

Conditions  affecting,  §4,pl4 

Effect  of  sizing  on,  §4,  p43 

Increasing  the,  §4,  pl6 
Revolving  reel.  Four-drum,  J6,  pl87 
Re-water,  Source  of,  §6,  p93 
RifiJers,  Construction  of,  §6,  p24 

with  electromagnets,  §6,  p25 

Two-run,  §6,  p24 
Right-hand  machine  (Def.),  §6,  p41 
Roll    (of    paper),    Starting    the,    §6,    p200 
Roll  bars.  Grinding  of,  §3,  pl9 
Roll  counterpoise,  §3,  p32 

journals,  couch  and  press.  Lubricat- 
ing of,  §6,  pl27 
Roll,  Beater,  §3,  p7 

Breast,  §6,  p53 
Roll,  couch.  Handling  of,  §6,  p86 

Putting  new  jacket  on,  §6,  p87 

Suction  in,  §6,  p91 
Roll,  Dandy  (Def.),  §6,  p61 

magnetic.     Description     of,      §1,     pl6 

Pinch,  §6,  pl81 

Spring,  §6,  pl79 

Stretch,  §6,  p73 

stretch.     Guiding    felt    by,     §6,     pl.54 

Suction  couch,  §6,  pl54 
Rolls,  Couch,  §6,  p64 

couch  and  press.  How  pressure  of  acti, 
§6,  p70 

Crown  of,  §6,  p52 

felt,  Balancing  of,  §6,  pl36 

felt,  Construction  and  sizes  of,  §6,  pi 36 

felt.  Size  of,  §6,  p52 
Rolls,  Fourdrinier,  §6,  p52 

Grooved,  §6,  p203 

Guide,  §6,  p60 

guide,  Auto-swing,  §6,  pll7 

(of  paper).  Improperly  wound,  §6,  pl90 

Number  of,  §6,  pl27 

Paper,  §6,  pi  18 
Rolls,  press.  Amount  of  crown  for,  §6,  pl34 
Construction  of ,  §6,  pl31 
Crowning  the,  §6,  pl31 
Details  of,  §6,  pl09 
Pressure  produced  by,  §6,  pl08 
Rubber-covered,  §6,  pl32 
Troubles   due   to   rubber   covering 
on,   §6,  pl33 
Weights  and  levers  for,  §6,  pi 07 
Rolls,  Smoothing,  §6,  pl42 

Adjusting  pressure  of,  §6,  pl43 

Crowning  of,  §6,  pl43 
Rolls,  Squaring  the,  §6,  p78 

suction,  Operation  of,  §6,  p70 

suction-couch,  Amount  of  vacuum  in, 
§6,  p70 


220 


INDEX 


Rolls,  Suction-press,  Lining  up,  §6,  pll2 

Construction  and  operation  of,  §6,  pi  12 
Rolls,  Sweat  and  smoothing,  Use  of,  §6,  pl82 
Rolls,  Table,  §6,  p54 

Leveling  and  lining-up,  §6,  p78 
Testing  squareness  of,  §6,  p77 
Roofs,  Influence  of,  in  drying,  §6,  pl75 
Rope  papers.  Sizing  of,  §4,  p47 
Rosin,  Cooking  of,  §4,  p30 
Extracted,  §4,  p25 
Grades  of,  §4,  p24 
Methods  of  saponifying,  §4,  p28 
Properties  and  uses  of,  §4,  p25 
Sources  of,  §4,  p24 
Rosin  size  and  alum.  Reaction  of,  §4,  p28 
Rosin  sizing  {Def.),  §4,  p23 

Process  of,  §4,  p23 
Rosin  spots.  Cause  of,  §4,  p44 
Rotary-boiler    process    for    cooking    waste 
papers,  §2,  p37 
Amount      and     strength      of 

liquor  for,   §2,  p40 
Dumping  the  boilers  in,    §2, 

p43 
Duration  of  cooking  in,    §2, 

p42 
Increasing  effect  of  friction  in, 

§2,  p42 
power  required  for,  §2,  p44 
Remarks  concerning,    §2,  p45 
Water  used  in,  §2,  p41 
Rubber  and  metal  in  rags,  §1,  pl2 
Rubber  coverings  on  rolls,  Troubles  due  to, 
§6,  pl33 

S 

Samples,  hand.  Making  of,  for  color  testing, 

§5,  p25 
Sand  trap,  §3,  pp6,  24 
Sap  brown  {Def.),  §5,  pll 
Saponification  table,  §4,  p30 
Saponifying,  Original  method  of,  §4,  p28 

rosin,  Modern  methods  of,  §4,  p29 
Save-all,  Cylinder  type  of,  §6,  pl8 
Inclined-wire  type  of,  §0,  p22 
Nash  type  of,  §6,  p23 
Polygonal-drum  type  of,  §6,  p20 
Shevlin  type  of,  §6,  p23 
Whitham  type  of,  §6,  p22 
Save-all  boxes,  §6,  pl6 
Save-alls  as  filters,  §6,  p23 
Score  cutter,  §6,  pl99 
Screening  waste-paper  stock,  §2,  p68 

Common  form  of  screen  for,  §2,  p68 
EfTect  of  poor  screening  of,  §2,  p69 
Furnishing   the   beaters  after,    §2, 

p68 
Sand  traps  for,  §2,  p68 
Screens,  Care  of,  §6,  p29 

Diaphragm,  or  flat,  §G,  p25 


Screens,  Rotary,  §6,  p30 

Inward-flow  type  of,  §6,  p31 

Outward-flow  type  of,  §6,  p32 
Screens,  Special  makes  of,  §6,  p32 

Vibrating,  §6,  p33 
Settling  tanks,  §6,  p20 
Shades,  Doctoring,  §5,  p42 

Matching,  §5,  p29 

Matching,  in  beater,  §5,  p41 

why  they  vary,  §5,  p34 
Shake  {Def.),  §6,  p51 

Amount  of,  §6,  p51 

connecting  rod,  §6,  p51 

Purpose  of,  §6,  p51 
Shake  head,  §6,  p51 
rails,  §6,  p46 
Shartle  attachment  for  beater,  §3,  p30 
Sheet,  paper.  Changing  width  of,  §6,  p44 
Shlick's  beater-hood  attachment,  §3,  p33 
Short  stock  {Def.),  §3,  p47 
Shower  pipes.  Size  and  action  of,  §6,  p92 
Shredders  for  waste  papers,  §2,  ppl9-24 

Power  required  for,  §2,  p23 
Siennas  {Def.),  §5,  p9 
Sieve  test  for  fillers,  §4,  pl9 
Siphons,  Use  of,  §6,  pl56 

and  dippers,  Comparison  of,  §6,  pl57 
Size,  Action  of,  on  dyestuffs,  §5,  p36 

Animal,  §4,  p23 

Effect  of  hard  water  on,  §4,  p37 

Furnishing,  to  beater,  §4,  p38 

Handling  diluted,  §4,  p37 

Methods  of  diluting,  §4,  p34 

Mill,  §4,  p30 

Neutral,  §4,  p30 

Reasons  for  diluting,  §4,  p32 

rosin,  and  alum.  Reaction  of,  §4,  p28 
Size  press,  §6,  pl76 
Sizing  {Def.),  §4,  p23 

Amount  of  alum  required  in,  §4,  p39 

in  beater,  §3,  p41 

Effect  of,  on  color,  strength,  etc.,  §4,  p43 

Free-rosin  vs.  neutral-rosin,  §4,  p33 

Reactions  in,  §4,  p39 

Reasons  for,  §4,  p23 

Rosin,  §4,  p23 

rosin.  Process  of,  §4,  p23 

Tub,  §4,  p23 

Use  of  casein  and  starch  in,  §4,  p42 

Use  of  soda  ash  in,  §4,  p25 

Use  of  sodium  sihcate  (water  glass)  in, 
§4,  p41 

of  various  papers,  §4,  p45 
Slice  {Def.),  §6,  p49 

details,  §6,  p50 

Purpose  of,  §6,  p49 
Slices,  Position  and  adjustment  of,  §6,  p50 

Regulating  the,  §6,  p81 
Slime  spots,  §6,  p45 
Slip-belt  drive,  §6,  pl93 


INDEX 


221 


Slitter  disks,  §6,  pl97 
Slitters,  §6,  pl96 
Slow  stock  {Def.),  §3,  p46 
Slush  pulps,  §3,  p40 
Smoothing  roll,  Use  of,  §6,  pl82 

Adjusting  pressure  of,  §6,  pl43 
Crowning  of,  §6,  pl43 
Smoothing  rolls,  §6,  pl42 
Soda,  Action  of,  on  dyestuffs,  §5,  p36 
Soda  ash,  Use  of,  in  sizing,  §4,  p25 
Sodium  silicate,  Use  of,  as  sizing  ingredient, 

§4,  p41 
Soft  stock  {Def.),  §6,  p82 
Sorting  rags,  §1,  plO 

rooms  for  waste  papers,  §2,  p9 
Sorting  waste  paper,  Bench  system  of,   §2, 
plO 
Carrier  system  of,  §2,  pl5 
Loss  in,  §2,  pl4 
Rate  of,  §2,  pl3 
Reducing  cost  of,  §2,  p25 
Using  discards  from,  §2,  p27 
Souring  the  Fourdrinier  wire,  §6,  p79 
Spear,  Use  of,  §6,  pi 68 
Spherical  boilers.  Use  of,  for  cooking   waste 

papers,  §2,  p44 
Spots,  froth.  Cause  of,  §4,  p44 
Hard  and  soft,  §6,  pl83 
rosin.  Cause  of,  §4,  p44 
Slime,  §6,  p4o 
Spray  dyeing,  §5,  pol 
Spring  roll,  §6,  pl79 

Standard  grades  of  waste  papers.  Subdivi- 
sions of,  §2,  p7 
solutions   for   testing   dyes,    §5,  p24 
Stands  and  reels.  Brake  bands  for,  §6,  pl95 
Stands,  Unreeling,  or  reeling-off,  §6,  pl95 
Starch,  Use  of,  in  sizing,  §4,  p42 
Steam  joints,  §6,  ppl48,  158 
Lubricating,  §6,  pl59 
Steam  traps,  §6,  pl62 

Bell  and  tilting  types  of,  §6,  pl63 
Steam  used  in  cooking.  Reducing  consump- 
tion of,  §2,  p33 
in  cooking  waste  papers.  Amount  of, 
§2,  p33 
Stobie  beater,  §3,  pl7 
Stock  {Def.),  §3,  p4;  §6,  pl3 
Circulation  of,  §6,  p3 
Effects  of  water  in,  §6,  p56 
Manner  of  running,  §6,  p82 
Necessity  for  uniform  flow  of,  §6,  p81 
Per  cent  of,  at  different  stages,  §6,  plOO 
Removal  of  water  from,  §6,  p56 
Short  or  long  (.De/.),  §3,  p47 
Slow  or  free  {Def.),  §3,  p46 
To  keep  water  in,  §6,  p83 
Straw  cellulose,  Influence  of  caustic  soda  on 
yield  of,  §1,  p58 
Manufacture  of,  §1,  p55 


Straw,  Characteristics  of,  §1,  p54 
Cooking  liquor  for,  §1,  p56 
Cooking  process  for,  §1,  p56 
Kinds  used  in  paper  making,  §1,  p55 
Preliminary  treatment  of,  §1,  p56 
Yield  of  cellulose  from,  §1,  p58 
Straw  pulp,  §1,  po4 

yellow,  Treatment  of,  §1,  p55 
Straw  stock.  Washing  and  bleaching  of,  §1, 

p57 
Straws,  Analysis  of,  §1,  p54 
Streaks,  Thin  and  heavy,  §6,  p46 
Strength  of  paper,  Effect  of  sizing  on,   §4, 

p43 
Stretch  roll,  §6,  p73 

Stretcher,    Automatic,    for   dryer   felts,  §6, 
pl51 
for  jackets,  §6,  p87 
Stretchers,  Press-felt,  §6,  pi  14 

felt.  Velocity  ratio  of,  §6,  pi  16 
String  catcher,  §3,  p30 
Stuff  {Def.),  §3,  pp4,  46 
Stuff  box.  Automatic,  §6,  pl4 
Stuff  chest  {Def.),  §6,  p5 

Horizontal,  §3,  p25;  §6,  p8 
Vertical,  §3,  p23 
Stuff  chests,  §3,  p22 

Capacity  and  size  of,  §6,  p7 
Care  of,  §6,  p8 
Packing  gland  for,  §3,  p26 
Stuff  pump.  Horsepower  of  and  work  of,  §6, 
pll 
Plunger,  §6,  p9 
Size  of,  §6,  plO 
Stuff  pumps,  §3,  p26 
Substantive  dyestuffs,  §5,  p7 
Suction  boxes.  Amount  of  vacuum  in,   §6, 
p57 
Braking  effects  of,  §6,  p91 
Felt,  §6,  pi  13 
Purpose  of,  §6,  p56 
Suction  couch  roll,  §6,  p68 

Suction  in,  §6,  p91 
Suction  press  rolls,  Construction  and  opera- 
tion of,  §6,  pi  12 
Lining  up,  §6,  pi  12 
Suction  pumps,  §6,  p58 
Suction,  Regulating  the,  §6,  p84 
Suction  roll,  how  it  acts,  §6,  p71 
Suction  rolls.  Amount  of  vacuum  in,  §6,  p70 
Construction    and  installation  of,ij§6 

p68 
Operation  of,  §6,  p70 
Sulphate  process  applied  to  esparto,  §1,  p53 
Sulphite  papers,  Sizing  of,  §4,  p46 
Sulphur  dyestuffs,  §5,  p8 
Surface  mark.  How  obtained,  §6,  p63 
Sweat  roll.  Use  of,  §6,  pl82 
Synthetic  resins,  §4,  p>42 


222 


INDEX 


Table  cuttings,  Source  of,  §1,  p4 
Table  rolls,  §6,  pp52,  .54 
Care  of,  §6,  poo 
Effects  produced  by,  §6,  poo 
Leveling  and  lining-up,  §6,  p78 
Size  of,  §6,  poo 
Testing  squareness  of,  |6,  p77 
Talc,  Occurrence  of,  §4,  p7 
Properties  of,  §4,  plO 
Treatment  of,  uses  of,  §4,  plO 
Tanks,  Settling,  §6,  p20 

storage,  Color-solution,  §5,  p33 
Tannin-mordanted  cotton.   How  prepared, 

§5,  p21 
Tension,  Controlling  the,  of  paper,  §6,  pl90 

Variable,  during  winding,  §6,  p20o 
Testing  dyestuffs.  Approximate  methods  of, 
§5,  p24 
dj'estuff  samples,  §5,  p22 
paper  for  mechanical  pulp,  §2,  pl2 
Testboard,  Sizing  of,  §4,  p47 
Thrasher  dust,  §1,  plO 
Thrasher,  Rag,  §1,  p9 
Trade  names  of  dyes,  §5,  p6 
Traps,  Sand,  §6,  p24 
Steam,  §6,  pl62 

steam.  Bell  and  tilting  types  of,  §6,  pl63 
Tub  coloring,  §5,  p49 
Tub  sizing  {Def.),  §4,  p23 
Two-sidedness  {Def.),  §5,  p43 


Ultramarines  {Def.),  §5,  pll 

Umbers  {Def.),  §5,  plO 

Umpherston  beater,  §3,  pll 

Uneven  bulking,  Corrections  for,  §6,  plS3 

Unreeling  stands,  §6,  pl9.5 


Vacuum,  Amount  of,  in  suction  couch  rolls, 
§6,  p70 

in  suction  boxes,  §6,  p57 
Vat  colors,  §o,  p8 

Manufacture  of,  §5,  pl3 
Venetian  red  (pigment),  §5,  plO 
Ventilation,  Influence  of,  in  drying  paper. 

§6,  pl70 
Vibrating  doctor,  §6,  pi  10 
Viscosity  theory  of  beating,  §3,  p54 
Vulcanized  papers.  Coloring  of,  §o,  p52 


W 


Wagg-Jordan  refiner,  §3,  p69 
Wallace-Masson   beater-roll   regulator,    §3 
p32 


Wallboard,  Sizing  of,  §4,  p40 
Washers,  Furnishmg  cooked  papers  for,  §2, 
p4.5 
Miscellaneous,   for   waste-paper  stock, 
|2,  p61 
Washing  cylinder  for  stock  in  beater,  §3,  p30 
Washing  engine,  §2,  po7 
for  rags,  §1,  p26 
Duration  of  and  effect  of  washing  by, 

§2,  po9 
Operations  with,  §2,  p58 
Removal  of  carbon  of  ink  from  paper 

by,  §2,  p59 
Removal  of  dirt  from  pulp  by,  §2,  po9 
Washing  esparto  stock,  §1,  p.52 
the  Fourdrinier  wire,  §6,  p80 
jute,  §1,  p43 

manila-rope  stock,  §1,  p41 
rags,  §1,  pp26-29 
rags.  Details  of,  §1,  p29 
rags,  Process  of,  §1,  p29 
straw  stock,  §1,  po7 
waste-paper  stock,  §2,  p57 
waste  papers  after  cooking,  Reason  for, 
§2,  p37 
Waste  paper.  Bench  system  of  sorting,   §2, 
plO 
Classification  of,  §2,  p4 
.    Loss  in  sorting,  §2,  pl4 

Market  quotations  on,  §2,  po 
Methods  of  recovery  of,  §2,  p3 
Price  fluctuation  of,  §2,  p8 
Standards  for,  §2,  p6 
Value  of,  §2,  p2 
Waste    papers,    Amount    of    dust    removed 
from,  §2,  pl8 
Amount  of  steam  used  in  cooking,  §2, 

p33 
Carrier  system  of  sorting,  §2,  plo 
Comparison    of    bench    and    carrier 

systems,  §2,  pl6 
Containers  for,  §2,  pl4 
cooked.  Removing  the,  §2,  p34 
cooking.  Furnishing  the  tank  for,  §2, 

p30 
Cooking  liquor  for,   §2,  p30 
Cooking    of,    by    mechanical     treat- 
ment, §2,  poO 
Cooking  of,  in  open  tanks,  §2,  p28 
Cooking  tank  for,  §2,  p29 
Duration  of  cook  for,  |2,  p32 
Dusting  of,  §2,  pl7 
Dusting,  after  shredding,  §2,  p24 
Extra  No.  1  or  No.  2  grades  of,  §2,  p7 
Fan  duster  for,  §2,  pl7 
Improved  cookmg  system  for,  §2,  p54 
Comparison    of,     with    open- 
tank  process,  §2,  p56 
De-fibering  and  de-inking  in, 
§2,   po6 


INDEX 


223 


Waste  papers,  Improved  cooking  system  for. 

Method  of  operation  in,  §2,  poo 

Layout  for  bench  system  of  sorting, 

§2,  pll  • 
mechanical  treatment  of.  Cost  of,  §2, 

p50 
mechanical  treatment  of.  Details  of, 

§2,  p50 
Methods  of  cooking,  §2,  p28 
New  tank  and  pumpmg  system  for, 

§2,  p.53 
No.  1  and  No.  2  grades  of,  §2,  p7 
Paper  obtained  by  mechanical  treat- 
ment of,  §2,  p49 
Power  required  for  dusting,   §2,  pl8 
Preparation  of  cooking  liquor  for,  §2, 

p3l 
Pulping  engine  for,  §2,  po3 
Railroad  duster  for,  §2,  pl7 
Rate  of  sorting  of,  §2,  pl3 
Reason  for  washing  after  cooking,  §2, 

p37 
Reducing  cost  of  sorting  of,   §2,  p25 
Rotary-boiler  process  for  cooking,  §2, 
p37 
Furnish  for,  §2,  p40 
Shrinkage  of  cooked,  on  washing,  §2, 

p66 
Special  No.  1  or  No.  2  grades,  §2,  p7 
standard  grades  of,  Subdivisions  of, 

§2.  p7 
Use  of,  §2,  pi 

Use  of  cooking  engine  for,  §2,  p46 
Use  of,  for  making  boards,  §2,  p57 
Use  of  spherical  boilers  for  cooking, 

§2,  p44  ■ 
Using  discards  from  sortmg  of,    §2, 
P27 
Waste-paper  pulper,  §3,  p3S 
shredders,  §2,  ppl9-24 
shredders.  Power  to  operate,  §2,  p23 
sorting  rooms,  §2,  p9 
stock,  Bleaching  of,  in   washing  engine, 
§2,  p64 
Choice  of,  §2,  p26 
cutters,  §2,  p21 
De-fibering  by  mechanical  treatment 

of,  §2,  p49 
De-inking  by  mechanical  treatment 

of,  §2,  p49 
Improving  quality  of,  §2,  p27 
Mechanical  treatment  of,  §2,  p48 
Miscellaneous  washers  for,  §2,  p61 
Purchasing  of,  §2,  p25 
Screening  of,  §2,  p68 
Three-cylinder  washer  for,  §2,  p64 
Washing  of,  §2,  p57 


Water  evaporated  by  dryers,  §6,  pi 70 

of  crystallization  (De/.),  §4,  pll 
Per  cent  of,  and  stock  at  different 

stages,  §6,  plOO 
Removal  of,  from  stock,   §6,  p.56 
Removing,  from  dryers,    §6,  ploo 
resistance  of  sized  papers,   §4,  p40 
in  stock.  Effects  of,   §6,  p56 
White  (Z>e/.),  §6,  pl6 
White,  back,  or  re-  {Def.),  §6,  p93 
Water  glass.  Use  of,  in  sizing,  §4,  p41 
Watermark,  Enlarging  the,  §6,  pS6 

Use  of  dandy  roll  for  making,   §6,  p61 
Weight   of  paper,    Uniformity   of,    §6,   pl2 
Wet  broke  {Def.),  §3,  pl7 
Wet  end  of  machine  (Def.),  §6,  p2 
Wet  machine.  Use  of,  for  de-watering  rag 

stock,  §1,  p36 
Whippers,  Press-felt,  §6,  pi  16 
White  print  (Def.),  as  applied  to  waste 

papers,  §2,  p27 
White  water  {Def.),  §6,  pl6 
flow  diagram,  §6,  pl7 
Source  of,  §6,  p93 
Whole-stuff  (Def.),  §3,  p46 
Wilkinite,  Use  of,  as  filler,  §4,  pl3 
Winder,  Compensating,  §6,  p204 
Constant-speed,  §6,  p201 
Drive  for,  §6,  pl93 
Driving  the,  §6,  p200  ' 
Four-roll,  §6,  p204 
trouble,  A  cause  of,  §6,  pl37 
Two-drum,  §6,  pl99 
Winding,  Variable  tension  during,  §6,  p205 
Wing,  or  fan,  duster,  §1,  pl5 
Wire,   Fourdrinier,   Amount  of  stretch   in, 
§6,  p78 
Cleaning  the,  §6,  p79 
Course  of,  §6,  p38 
Elevating  the,  §6,  p73 
How   paper  should   be   taken   off   the, 

§6,  p71 
Making,  to  run  true,  §6,  p92 
Mesh  of,  §6,  p94 
Putting  on  new,  §6,  p76 
Removing  old,  §6,  p74 
Souring  the,  §6,  p79 
Starting  the,  §6,  p94 
Starting  a  new,  §6,  p7S 
Stretching  the,  §6,  p73 
Varying  the  tension  of  the,  §6,  p73 
Washing  the,  §6,  p80 
Wire,  kinks  in,  Removal  of,  §6,  p81 
guide,  Action  of,  §6,  p80 
Passing  paper  from,  to  felt,  §6,  p39 
Wove  paper  (Def.),  §6,  p61 
Wrapping  papers.  Sizing  of,  §4,  p46 
Wrinkles  in  rolls  of  paper,  §6,  p205 
WritiuE  papers,  Sizing  of,  §4,  p46 


ROBERTSON  PULP  &  PAPFP  i  ar 
RALEIGH,  H.  C.  27607